SEC Info  
    Home      Search      My Interests      Help      Sign In      Please Sign In

Harsco Corp – ‘10-K’ for 12/31/19 – ‘EX-101.DEF’

On:  Friday, 2/21/20, at 2:29pm ET   ·   For:  12/31/19   ·   Accession #:  45876-20-26   ·   File #:  1-03970

Previous ‘10-K’:  ‘10-K’ on 2/21/19 for 12/31/18   ·   Next:  ‘10-K’ on 2/25/21 for 12/31/20   ·   Latest:  ‘10-K’ on 2/29/24 for 12/31/23   ·   2 References:   

Find Words in Filings emoji
 
  in    Show  and   Hints

  As Of               Filer                 Filing    For·On·As Docs:Size

 2/21/20  Harsco Corp                       10-K       12/31/19  124:27M

Annual Report   —   Form 10-K   —   Sect. 13 / 15(d) – SEA’34
Filing Table of Contents

Document/Exhibit                   Description                      Pages   Size 

 1: 10-K        Annual Report                                       HTML   3.43M 
 2: EX-4.A      Instrument Defining the Rights of Security Holders  HTML     57K 
 3: EX-21       Subsidiaries List                                   HTML     91K 
 4: EX-23       Consent of Experts or Counsel                       HTML     32K 
 5: EX-31.1     Certification -- §302 - SOA'02                      HTML     39K 
 6: EX-31.2     Certification -- §302 - SOA'02                      HTML     38K 
 7: EX-32       Certification -- §906 - SOA'02                      HTML     35K 
57: R1          Document and Entity Information                     HTML     93K 
104: R2          Consolidated Balance Sheets                         HTML    176K  
88: R3          Consolidated Balance Sheets (Parenthetical)         HTML     41K 
20: R4          Consolidated Statements of Operations               HTML    174K 
59: R5          Consolidated Statements of Comprehensive Income     HTML     70K 
                (Loss)                                                           
105: R6          Consolidated Statements of Comprehensive Income     HTML     46K  
                (Loss) (Parenthetical)                                           
89: R7          Consolidated Statements of Cash Flows               HTML    188K 
16: R8          Consolidated Statements of Changes in Equity        HTML     87K 
64: R9          Consolidated Statements of Changes in Equity        HTML     47K 
                (Parenthetical)                                                  
31: R10         Summary of Significant Accounting Policies          HTML    115K 
47: R11         Recently Adopted and Recently Issued Accounting     HTML     47K 
                Standards                                                        
111: R12         Acquisitions and Dispositions                       HTML    239K  
72: R13         Accounts Receivable and Inventories                 HTML     81K 
30: R14         Property, Plant and Equipment                       HTML     54K 
46: R15         Goodwill and Other Intangible Assets                HTML    104K 
110: R16         Debt and Credit Agreements                          HTML     87K  
71: R17         Leases                                              HTML    217K 
32: R18         Employee Benefit Plans                              HTML    427K 
45: R19         Income Taxes                                        HTML    220K 
109: R20         Commitments and Contingencies                       HTML     71K  
95: R21         Capital Stock                                       HTML     97K 
24: R22         Stock-Based Compensation                            HTML    213K 
69: R23         Financial Instruments                               HTML    236K 
108: R24         Information by Segment and Geographic Area          HTML    178K  
94: R25         Revenue Recognition                                 HTML    257K 
23: R26         Other Expenses                                      HTML    101K 
68: R27         Components of Accumulated Other Comprehensive Loss  HTML    160K 
107: R28         Schedule Ii. Valuation and Qualifying Accounts      HTML     77K  
96: R29         Subsequent Event (Notes)                            HTML     35K 
76: R30         Summary of Significant Accounting Policies          HTML    169K 
                (Policies)                                                       
112: R31         Summary of Significant Accounting Policies          HTML     54K  
                (Tables)                                                         
43: R32         Recently Adopted and Recently Issued Accounting     HTML     36K 
                Standards (Tables)                                               
25: R33         Acquisitions and Dispositions (Tables)              HTML    222K 
77: R34         Accounts Receivable and Inventories (Tables)        HTML     81K 
113: R35         Property, Plant and Equipment (Tables)              HTML     54K  
44: R36         Goodwill and Other Intangible Assets (Tables)       HTML    104K 
26: R37         Debt and Credit Agreements (Tables)                 HTML     77K 
74: R38         Leases (Tables)                                     HTML    117K 
115: R39         Employee Benefit Plans (Tables)                     HTML    435K  
86: R40         Income Taxes (Tables)                               HTML    211K 
97: R41         Capital Stock (Tables)                              HTML    101K 
66: R42         Stock-Based Compensation (Tables)                   HTML    213K 
21: R43         Financial Instruments (Tables)                      HTML    216K 
87: R44         Information by Segment and Geographic Area          HTML    180K 
                (Tables)                                                         
98: R45         Revenue Recognition (Tables)                        HTML    243K 
67: R46         Other Expenses (Tables)                             HTML     93K 
22: R47         Components of Accumulated Other Comprehensive Loss  HTML    162K 
                (Tables)                                                         
85: R48         Summary of Significant Accounting Policies          HTML     40K 
                (Details)                                                        
99: R49         Summary of Significant Accounting Policies          HTML     59K 
                (Details 3)                                                      
120: R50         Summary of Significant Accounting Policies          HTML     36K  
                (Details 4)                                                      
79: R51         Recently Adopted and Recently Issued Accounting     HTML     39K 
                Standards - Narrative (Details)                                  
40: R52         Acquisitions and Dispositions - Narrative           HTML    115K 
                (Details)                                                        
55: R53         Acquisitions and Dispositions - Summary of Assets   HTML    139K 
                Acquired and Liabilities Assumed (Details)                       
119: R54         Acquisitions and Dispositions - Summary of          HTML     59K  
                Intangible Assets and Amortization Periods                       
                (Details)                                                        
78: R55         Acquisitions and Dispositions - Summary of Changes  HTML     50K 
                in Fair Value of Contingent Consideration                        
                (Details)                                                        
39: R56         Acquisitions and Dispositions - Pro Forma           HTML     42K 
                Information (Details)                                            
54: R57         Acquisitions and Dispositions - Assets and          HTML    111K 
                Liabilities Held For Sale (Details)                              
116: R58         Acquisitions and Dispositions - Summary of Key      HTML     72K  
                Financial Information (Details)                                  
80: R59         Acquisitions and Dispositions - Summary of Cash     HTML     40K 
                Flow Information (Details)                                       
15: R60         Accounts Receivable and Inventories (Details)       HTML     94K 
62: R61         Property, Plant and Equipment (Details)             HTML     66K 
102: R62         Goodwill and Other Intangible Assets (Details)      HTML     49K  
92: R63         Goodwill and Other Intangible Assets (Details 2)    HTML     77K 
14: R64         Debt and Credit Agreements - Schedule of Long Term  HTML     59K 
                Debt (Details)                                                   
61: R65         Debt and Credit Agreements - Schedule of            HTML     44K 
                Maturities of Long Term Debt (Details)                           
101: R66         Debt and Credit Agreements - Narrative (Details)    HTML    126K  
91: R67         Debt and Credit Agreements - Outstanding Amounts    HTML     44K 
                Under Revolving Credit Facility (Details)                        
18: R68         Leases - Supplemental Cash Flow Information         HTML     45K 
                (Details)                                                        
56: R69         Leases - Supplemental Income Statement Information  HTML     49K 
                (Details)                                                        
49: R70         Leases - Supplemental Balance Sheet Information     HTML     45K 
                (Details)                                                        
36: R71         Leases - Supplemental Lease Information (Details)   HTML     42K 
82: R72         Leases - Schedule of Future Lease Maturities        HTML     72K 
                (Details)                                                        
122: R73         Leases - Schedule of Future Minimum Payments        HTML     50K  
                (Details)                                                        
50: R74         Leases - Narrative (Details)                        HTML     35K 
37: R75         Employee Benefit Plans (Details)                    HTML     84K 
83: R76         Employee Benefit Plans (Details 2)                  HTML    196K 
123: R77         Employee Benefit Plans (Details 3)                  HTML    248K  
53: R78         Employee Benefit Plans (Details 4)                  HTML     35K 
34: R79         Income Taxes (Details)                              HTML     77K 
48: R80         Income Taxes (Details 2)                            HTML     87K 
35: R81         Income Taxes (Details 3)                            HTML     86K 
81: R82         Income Taxes (Details 4)                            HTML    139K 
121: R83         Income Taxes (Details 5)                            HTML     77K  
51: R84         Commitments and Contingencies (Details)             HTML    122K 
38: R85         Capital Stock (Details)                             HTML     44K 
84: R86         Capital Stock (Details 2)                           HTML     90K 
124: R87         Capital Stock (Details 3)                           HTML     45K  
52: R88         Stock-Based Compensation (Restricted Stock)         HTML    141K 
                (Details)                                                        
33: R89         Stock-Based Compensation (Stock Appreciation        HTML    222K 
                Rights) (Details)                                                
17: R90         Stock-Based Compensation (Performance Stock Units)  HTML    107K 
                (Details)                                                        
63: R91         Stock-Based Compensation (Stock Options) (Details)  HTML     55K 
103: R92         Financial Instruments - Narrative (Details)         HTML    107K  
93: R93         Financial Instruments - Fair Value of Outstanding   HTML     73K 
                Derivative Contracts Recorded as Assets and                      
                Liabilities (Details)                                            
13: R94         Financial Instruments - Effect of Derivative        HTML    117K 
                Instruments on the Consolidated Statements of                    
                Operations and the Consolidated Statements of                    
                Comprehensive Income (Loss) (Details)                            
60: R95         Financial Instruments - Effect of Derivatives       HTML     81K 
                (Details)                                                        
100: R96         Information by Segment and Geographic Area          HTML     55K  
                (Details)                                                        
90: R97         Information by Segment and Geographic Area          HTML     45K 
                (Details 2)                                                      
19: R98         Information by Segment and Geographic Area          HTML     83K 
                (Details 3)                                                      
58: R99         Revenue Recognition - Summary of Revenues by        HTML    151K 
                Primary Geographical Markets (Details)                           
41: R100        Revenue Recognition - Narrative (Details)           HTML    139K 
27: R101        Revenue Recognition - Performance Obligation        HTML     53K 
                Period Narrative (Details)                                       
73: R102        Other Expenses (Details)                            HTML     68K 
114: R103        Components of Accumulated Other Comprehensive Loss  HTML     98K  
                (Details)                                                        
42: R104        Components of Accumulated Other Comprehensive Loss  HTML     97K 
                (Details 2)                                                      
28: R105        Schedule Ii. Valuation and Qualifying Accounts      HTML     65K 
                (Details)                                                        
75: R106        Subsequent Event (Details)                          HTML     37K 
65: R9999       Uncategorized Items - hsc-201910kxq42019.htm        HTML     36K 
29: XML         IDEA XML File -- Filing Summary                      XML    233K 
70: XML         XBRL Instance -- hsc-201910kxq42019_htm              XML   8.35M 
118: EXCEL       IDEA Workbook of Financial Reports                  XLSX    195K  
 9: EX-101.CAL  XBRL Calculations -- hsc-20191231_cal                XML    469K 
10: EX-101.DEF  XBRL Definitions -- hsc-20191231_def                 XML   1.77M 
11: EX-101.LAB  XBRL Labels -- hsc-20191231_lab                      XML   3.73M 
12: EX-101.PRE  XBRL Presentations -- hsc-20191231_pre               XML   2.36M 
 8: EX-101.SCH  XBRL Schema -- hsc-20191231                          XSD    335K 
106: JSON        XBRL Instance as JSON Data -- MetaLinks              728±  1.12M  
117: ZIP         XBRL Zipped Folder -- 0000045876-20-000026-xbrl      Zip    805K  


‘EX-101.DEF’   —   XBRL Definitions — hsc-20191231_def


This Exhibit is an XBRL XML File.


                                                                                                                                                                                
<?xml version="1.0" encoding="windows-1252"?>
<!-- XBRL Document Created with Wdesk from Workiva -->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<link:roleRef roleURI="http://www.harsco.com/role/AccountsReceivableAndInventories" xlink:href="hsc-20191231.xsd#AccountsReceivableAndInventories" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AccountsReceivableAndInventoriesDetails" xlink:href="hsc-20191231.xsd#AccountsReceivableAndInventoriesDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AccountsReceivableAndInventoriesTables" xlink:href="hsc-20191231.xsd#AccountsReceivableAndInventoriesTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AcquisitionsAndDispositions" xlink:href="hsc-20191231.xsd#AcquisitionsAndDispositions" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AcquisitionsAndDispositionsAssetsAndLiabilitiesHeldForSaleDetails" xlink:href="hsc-20191231.xsd#AcquisitionsAndDispositionsAssetsAndLiabilitiesHeldForSaleDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AcquisitionsAndDispositionsNarrativeDetails" xlink:href="hsc-20191231.xsd#AcquisitionsAndDispositionsNarrativeDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AcquisitionsAndDispositionsProFormaInformationDetails" xlink:href="hsc-20191231.xsd#AcquisitionsAndDispositionsProFormaInformationDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AcquisitionsAndDispositionsSummaryOfAssetsAcquiredAndLiabilitiesAssumedDetails" xlink:href="hsc-20191231.xsd#AcquisitionsAndDispositionsSummaryOfAssetsAcquiredAndLiabilitiesAssumedDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AcquisitionsAndDispositionsSummaryOfCashFlowInformationDetails" xlink:href="hsc-20191231.xsd#AcquisitionsAndDispositionsSummaryOfCashFlowInformationDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AcquisitionsAndDispositionsSummaryOfChangesInFairValueOfContingentConsiderationDetails" xlink:href="hsc-20191231.xsd#AcquisitionsAndDispositionsSummaryOfChangesInFairValueOfContingentConsiderationDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AcquisitionsAndDispositionsSummaryOfIntangibleAssetsAndAmortizationPeriodsDetails" xlink:href="hsc-20191231.xsd#AcquisitionsAndDispositionsSummaryOfIntangibleAssetsAndAmortizationPeriodsDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AcquisitionsAndDispositionsSummaryOfKeyFinancialInformationDetails" xlink:href="hsc-20191231.xsd#AcquisitionsAndDispositionsSummaryOfKeyFinancialInformationDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/AcquisitionsAndDispositionsTables" xlink:href="hsc-20191231.xsd#AcquisitionsAndDispositionsTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/CapitalStock" xlink:href="hsc-20191231.xsd#CapitalStock" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/CapitalStockDetails" xlink:href="hsc-20191231.xsd#CapitalStockDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/CapitalStockDetails2" xlink:href="hsc-20191231.xsd#CapitalStockDetails2" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/CapitalStockDetails3" xlink:href="hsc-20191231.xsd#CapitalStockDetails3" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/CapitalStockTables" xlink:href="hsc-20191231.xsd#CapitalStockTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/CommitmentsAndContingencies" xlink:href="hsc-20191231.xsd#CommitmentsAndContingencies" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/CommitmentsAndContingenciesDetails" xlink:href="hsc-20191231.xsd#CommitmentsAndContingenciesDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ComponentsOfAccumulatedOtherComprehensiveLoss" xlink:href="hsc-20191231.xsd#ComponentsOfAccumulatedOtherComprehensiveLoss" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ComponentsOfAccumulatedOtherComprehensiveLossDetails" xlink:href="hsc-20191231.xsd#ComponentsOfAccumulatedOtherComprehensiveLossDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ComponentsOfAccumulatedOtherComprehensiveLossDetails2" xlink:href="hsc-20191231.xsd#ComponentsOfAccumulatedOtherComprehensiveLossDetails2" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ComponentsOfAccumulatedOtherComprehensiveLossTables" xlink:href="hsc-20191231.xsd#ComponentsOfAccumulatedOtherComprehensiveLossTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ConsolidatedBalanceSheets" xlink:href="hsc-20191231.xsd#ConsolidatedBalanceSheets" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="hsc-20191231.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="hsc-20191231.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ConsolidatedStatementsOfChangesInEquity" xlink:href="hsc-20191231.xsd#ConsolidatedStatementsOfChangesInEquity" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ConsolidatedStatementsOfChangesInEquityParenthetical" xlink:href="hsc-20191231.xsd#ConsolidatedStatementsOfChangesInEquityParenthetical" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ConsolidatedStatementsOfComprehensiveIncomeLoss" xlink:href="hsc-20191231.xsd#ConsolidatedStatementsOfComprehensiveIncomeLoss" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ConsolidatedStatementsOfComprehensiveIncomeLossParenthetical" xlink:href="hsc-20191231.xsd#ConsolidatedStatementsOfComprehensiveIncomeLossParenthetical" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ConsolidatedStatementsOfOperations" xlink:href="hsc-20191231.xsd#ConsolidatedStatementsOfOperations" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/DebtAndCreditAgreements" xlink:href="hsc-20191231.xsd#DebtAndCreditAgreements" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/DebtAndCreditAgreementsNarrativeDetails" xlink:href="hsc-20191231.xsd#DebtAndCreditAgreementsNarrativeDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/DebtAndCreditAgreementsOutstandingAmountsUnderRevolvingCreditFacilityDetails" xlink:href="hsc-20191231.xsd#DebtAndCreditAgreementsOutstandingAmountsUnderRevolvingCreditFacilityDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/DebtAndCreditAgreementsScheduleOfLongTermDebtDetails" xlink:href="hsc-20191231.xsd#DebtAndCreditAgreementsScheduleOfLongTermDebtDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/DebtAndCreditAgreementsScheduleOfMaturitiesOfLongTermDebtDetails" xlink:href="hsc-20191231.xsd#DebtAndCreditAgreementsScheduleOfMaturitiesOfLongTermDebtDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/DebtAndCreditAgreementsTables" xlink:href="hsc-20191231.xsd#DebtAndCreditAgreementsTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/DocumentAndEntityInformation" xlink:href="hsc-20191231.xsd#DocumentAndEntityInformation" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/EmployeeBenefitPlans" xlink:href="hsc-20191231.xsd#EmployeeBenefitPlans" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/EmployeeBenefitPlansDetails" xlink:href="hsc-20191231.xsd#EmployeeBenefitPlansDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/EmployeeBenefitPlansDetails2" xlink:href="hsc-20191231.xsd#EmployeeBenefitPlansDetails2" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/EmployeeBenefitPlansDetails3" xlink:href="hsc-20191231.xsd#EmployeeBenefitPlansDetails3" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/EmployeeBenefitPlansDetails4" xlink:href="hsc-20191231.xsd#EmployeeBenefitPlansDetails4" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/EmployeeBenefitPlansTables" xlink:href="hsc-20191231.xsd#EmployeeBenefitPlansTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/FinancialInstruments" xlink:href="hsc-20191231.xsd#FinancialInstruments" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/FinancialInstrumentsEffectOfDerivativeInstrumentsOnConsolidatedStatementsOfOperationsAndConsolidatedStatementsOfComprehensiveIncomeLossDetails" xlink:href="hsc-20191231.xsd#FinancialInstrumentsEffectOfDerivativeInstrumentsOnConsolidatedStatementsOfOperationsAndConsolidatedStatementsOfComprehensiveIncomeLossDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/FinancialInstrumentsEffectOfDerivativesDetails" xlink:href="hsc-20191231.xsd#FinancialInstrumentsEffectOfDerivativesDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/FinancialInstrumentsFairValueOfOutstandingDerivativeContractsRecordedAsAssetsAndLiabilitiesDetails" xlink:href="hsc-20191231.xsd#FinancialInstrumentsFairValueOfOutstandingDerivativeContractsRecordedAsAssetsAndLiabilitiesDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/FinancialInstrumentsNarrativeDetails" xlink:href="hsc-20191231.xsd#FinancialInstrumentsNarrativeDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/FinancialInstrumentsTables" xlink:href="hsc-20191231.xsd#FinancialInstrumentsTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/GoodwillAndOtherIntangibleAssets" xlink:href="hsc-20191231.xsd#GoodwillAndOtherIntangibleAssets" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/GoodwillAndOtherIntangibleAssetsDetails" xlink:href="hsc-20191231.xsd#GoodwillAndOtherIntangibleAssetsDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/GoodwillAndOtherIntangibleAssetsDetails2" xlink:href="hsc-20191231.xsd#GoodwillAndOtherIntangibleAssetsDetails2" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/GoodwillAndOtherIntangibleAssetsTables" xlink:href="hsc-20191231.xsd#GoodwillAndOtherIntangibleAssetsTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/IncomeTaxes" xlink:href="hsc-20191231.xsd#IncomeTaxes" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/IncomeTaxesDetails" xlink:href="hsc-20191231.xsd#IncomeTaxesDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/IncomeTaxesDetails2" xlink:href="hsc-20191231.xsd#IncomeTaxesDetails2" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/IncomeTaxesDetails3" xlink:href="hsc-20191231.xsd#IncomeTaxesDetails3" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/IncomeTaxesDetails4" xlink:href="hsc-20191231.xsd#IncomeTaxesDetails4" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/IncomeTaxesDetails5" xlink:href="hsc-20191231.xsd#IncomeTaxesDetails5" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/IncomeTaxesTables" xlink:href="hsc-20191231.xsd#IncomeTaxesTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/InformationBySegmentAndGeographicArea" xlink:href="hsc-20191231.xsd#InformationBySegmentAndGeographicArea" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/InformationBySegmentAndGeographicAreaDetails" xlink:href="hsc-20191231.xsd#InformationBySegmentAndGeographicAreaDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/InformationBySegmentAndGeographicAreaDetails2" xlink:href="hsc-20191231.xsd#InformationBySegmentAndGeographicAreaDetails2" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/InformationBySegmentAndGeographicAreaDetails3" xlink:href="hsc-20191231.xsd#InformationBySegmentAndGeographicAreaDetails3" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/InformationBySegmentAndGeographicAreaDetails4" xlink:href="hsc-20191231.xsd#InformationBySegmentAndGeographicAreaDetails4" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/InformationBySegmentAndGeographicAreaTables" xlink:href="hsc-20191231.xsd#InformationBySegmentAndGeographicAreaTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/Leases" xlink:href="hsc-20191231.xsd#Leases" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/LeasesNarrativeDetails" xlink:href="hsc-20191231.xsd#LeasesNarrativeDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/LeasesScheduleOfFutureLeaseMaturitiesDetails" xlink:href="hsc-20191231.xsd#LeasesScheduleOfFutureLeaseMaturitiesDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/LeasesScheduleOfFutureMinimumPaymentsDetails" xlink:href="hsc-20191231.xsd#LeasesScheduleOfFutureMinimumPaymentsDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/LeasesSupplementalBalanceSheetInformationDetails" xlink:href="hsc-20191231.xsd#LeasesSupplementalBalanceSheetInformationDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/LeasesSupplementalCashFlowInformationDetails" xlink:href="hsc-20191231.xsd#LeasesSupplementalCashFlowInformationDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/LeasesSupplementalIncomeStatementInformationDetails" xlink:href="hsc-20191231.xsd#LeasesSupplementalIncomeStatementInformationDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/LeasesSupplementalLeaseInformationDetails" xlink:href="hsc-20191231.xsd#LeasesSupplementalLeaseInformationDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/LeasesTables" xlink:href="hsc-20191231.xsd#LeasesTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/OtherExpenses" xlink:href="hsc-20191231.xsd#OtherExpenses" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/OtherExpensesDetails" xlink:href="hsc-20191231.xsd#OtherExpensesDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/OtherExpensesTables" xlink:href="hsc-20191231.xsd#OtherExpensesTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/PropertyPlantAndEquipment" xlink:href="hsc-20191231.xsd#PropertyPlantAndEquipment" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/PropertyPlantAndEquipmentDetails" xlink:href="hsc-20191231.xsd#PropertyPlantAndEquipmentDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/PropertyPlantAndEquipmentTables" xlink:href="hsc-20191231.xsd#PropertyPlantAndEquipmentTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/RecentlyAdoptedAndRecentlyIssuedAccountingStandards" xlink:href="hsc-20191231.xsd#RecentlyAdoptedAndRecentlyIssuedAccountingStandards" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/RecentlyAdoptedAndRecentlyIssuedAccountingStandardsNarrativeDetails" xlink:href="hsc-20191231.xsd#RecentlyAdoptedAndRecentlyIssuedAccountingStandardsNarrativeDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/RecentlyAdoptedAndRecentlyIssuedAccountingStandardsTables" xlink:href="hsc-20191231.xsd#RecentlyAdoptedAndRecentlyIssuedAccountingStandardsTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/RevenueRecognition" xlink:href="hsc-20191231.xsd#RevenueRecognition" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/RevenueRecognitionNarrativeDetails" xlink:href="hsc-20191231.xsd#RevenueRecognitionNarrativeDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/RevenueRecognitionPerformanceObligationPeriodNarrativeDetails" xlink:href="hsc-20191231.xsd#RevenueRecognitionPerformanceObligationPeriodNarrativeDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/RevenueRecognitionSummaryOfRevenuesByPrimaryGeographicalMarketsDetails" xlink:href="hsc-20191231.xsd#RevenueRecognitionSummaryOfRevenuesByPrimaryGeographicalMarketsDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/RevenueRecognitionTables" xlink:href="hsc-20191231.xsd#RevenueRecognitionTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ScheduleIiValuationAndQualifyingAccounts" xlink:href="hsc-20191231.xsd#ScheduleIiValuationAndQualifyingAccounts" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/ScheduleIiValuationAndQualifyingAccountsDetails" xlink:href="hsc-20191231.xsd#ScheduleIiValuationAndQualifyingAccountsDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/StockBasedCompensation" xlink:href="hsc-20191231.xsd#StockBasedCompensation" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/StockBasedCompensationPerformanceStockUnitsDetails" xlink:href="hsc-20191231.xsd#StockBasedCompensationPerformanceStockUnitsDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/StockBasedCompensationRestrictedStockDetails" xlink:href="hsc-20191231.xsd#StockBasedCompensationRestrictedStockDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/StockBasedCompensationStockAppreciationRightsDetails" xlink:href="hsc-20191231.xsd#StockBasedCompensationStockAppreciationRightsDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/StockBasedCompensationStockOptionsDetails" xlink:href="hsc-20191231.xsd#StockBasedCompensationStockOptionsDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/StockBasedCompensationTables" xlink:href="hsc-20191231.xsd#StockBasedCompensationTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/SubsequentEventDetails" xlink:href="hsc-20191231.xsd#SubsequentEventDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/SubsequentEventNotes" xlink:href="hsc-20191231.xsd#SubsequentEventNotes" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/SubsequentEventTables" xlink:href="hsc-20191231.xsd#SubsequentEventTables" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/SummaryOfSignificantAccountingPolicies" xlink:href="hsc-20191231.xsd#SummaryOfSignificantAccountingPolicies" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:href="hsc-20191231.xsd#SummaryOfSignificantAccountingPoliciesDetails" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesDetails2" xlink:href="hsc-20191231.xsd#SummaryOfSignificantAccountingPoliciesDetails2" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesDetails3" xlink:href="hsc-20191231.xsd#SummaryOfSignificantAccountingPoliciesDetails3" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesDetails4" xlink:href="hsc-20191231.xsd#SummaryOfSignificantAccountingPoliciesDetails4" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="hsc-20191231.xsd#SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple"/>
<link:roleRef roleURI="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:href="hsc-20191231.xsd#SummaryOfSignificantAccountingPoliciesTables" xlink:type="simple"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/AccountsReceivableAndInventories" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/AccountsReceivableAndInventoriesDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_A74CC07EE45DBEA3956E591AA7346919" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_608648C46A9307F20F53591AA734D69A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_A74CC07EE45DBEA3956E591AA7346919" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_608648C46A9307F20F53591AA734D69A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ContractAxis" xlink:label="loc_hsc_ContractAxis_99F8CA4CD3037ABC682D591AA73432C8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_608648C46A9307F20F53591AA734D69A" xlink:to="loc_hsc_ContractAxis_99F8CA4CD3037ABC682D591AA73432C8" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ContractDomain" xlink:label="loc_hsc_ContractDomain_B1F0E1ADAE438B2748E2591AA734CAEA_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_hsc_ContractAxis_99F8CA4CD3037ABC682D591AA73432C8" xlink:to="loc_hsc_ContractDomain_B1F0E1ADAE438B2748E2591AA734CAEA_default" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ContractDomain" xlink:label="loc_hsc_ContractDomain_B1F0E1ADAE438B2748E2591AA734CAEA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_hsc_ContractAxis_99F8CA4CD3037ABC682D591AA73432C8" xlink:to="loc_hsc_ContractDomain_B1F0E1ADAE438B2748E2591AA734CAEA" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_Contract2Member" xlink:label="loc_hsc_Contract2Member_B0A5FCDB6DAE34F5B415591AA73495E5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_ContractDomain_B1F0E1ADAE438B2748E2591AA734CAEA" xlink:to="loc_hsc_Contract2Member_B0A5FCDB6DAE34F5B415591AA73495E5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MajorCustomersAxis" xlink:label="loc_srt_MajorCustomersAxis_00FAB38605D20B50CF3D591AA734B792" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_608648C46A9307F20F53591AA734D69A" xlink:to="loc_srt_MajorCustomersAxis_00FAB38605D20B50CF3D591AA734B792" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_CC244428DEE282869B40591AA734F688_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_00FAB38605D20B50CF3D591AA734B792" xlink:to="loc_srt_NameOfMajorCustomerDomain_CC244428DEE282869B40591AA734F688_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_CC244428DEE282869B40591AA734F688" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_00FAB38605D20B50CF3D591AA734B792" xlink:to="loc_srt_NameOfMajorCustomerDomain_CC244428DEE282869B40591AA734F688" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SBBMember" xlink:label="loc_hsc_SBBMember_F2F0A3F773BCCD4878CD591AA734C0F5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_CC244428DEE282869B40591AA734F688" xlink:to="loc_hsc_SBBMember_F2F0A3F773BCCD4878CD591AA734C0F5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsReceivableNetCurrentAbstract" xlink:label="loc_us-gaap_AccountsReceivableNetCurrentAbstract_42F21E846D4596B859EE591AA7343E14" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_A74CC07EE45DBEA3956E591AA7346919" xlink:to="loc_us-gaap_AccountsReceivableNetCurrentAbstract_42F21E846D4596B859EE591AA7343E14" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsReceivableGrossCurrent" xlink:label="loc_us-gaap_AccountsReceivableGrossCurrent_31FFD5BFB5175AF7473E591AA7343335" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsReceivableNetCurrentAbstract_42F21E846D4596B859EE591AA7343E14" xlink:to="loc_us-gaap_AccountsReceivableGrossCurrent_31FFD5BFB5175AF7473E591AA7343335" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_E0261F9FFAB3A5DC6A30591AA7343349" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsReceivableNetCurrentAbstract_42F21E846D4596B859EE591AA7343E14" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_E0261F9FFAB3A5DC6A30591AA7343349" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_1E0C257287CB41FA274D591AA7344958" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsReceivableNetCurrentAbstract_42F21E846D4596B859EE591AA7343E14" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_1E0C257287CB41FA274D591AA7344958" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InsuranceSettlementsReceivable" xlink:label="loc_us-gaap_InsuranceSettlementsReceivable_7FF84D703D3C8BDAFD49591AA734DA66" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsReceivableNetCurrentAbstract_42F21E846D4596B859EE591AA7343E14" xlink:to="loc_us-gaap_InsuranceSettlementsReceivable_7FF84D703D3C8BDAFD49591AA734DA66" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherReceivablesNetCurrent" xlink:label="loc_us-gaap_OtherReceivablesNetCurrent_4ECE0D65C498FD006B1E591AA734BC02" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsReceivableNetCurrentAbstract_42F21E846D4596B859EE591AA7343E14" xlink:to="loc_us-gaap_OtherReceivablesNetCurrent_4ECE0D65C498FD006B1E591AA734BC02" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProvisionForDoubtfulAccounts" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_07F9D8A9662FB84B4C6D591AA73469A5" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsReceivableNetCurrentAbstract_42F21E846D4596B859EE591AA7343E14" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_07F9D8A9662FB84B4C6D591AA73469A5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InventoryNetItemsNetOfReserveAlternativeAbstract" xlink:label="loc_us-gaap_InventoryNetItemsNetOfReserveAlternativeAbstract_F9BB87C0E25C14517971591AA734BA10" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_A74CC07EE45DBEA3956E591AA7346919" xlink:to="loc_us-gaap_InventoryNetItemsNetOfReserveAlternativeAbstract_F9BB87C0E25C14517971591AA734BA10" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:label="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_BA07094248E95CFE61D8591AA7344760" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryNetItemsNetOfReserveAlternativeAbstract_F9BB87C0E25C14517971591AA734BA10" xlink:to="loc_us-gaap_InventoryFinishedGoodsNetOfReserves_BA07094248E95CFE61D8591AA7344760" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InventoryWorkInProcessNetOfReserves" xlink:label="loc_us-gaap_InventoryWorkInProcessNetOfReserves_2930BD877E2A8CFBCC87591AA734F525" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryNetItemsNetOfReserveAlternativeAbstract_F9BB87C0E25C14517971591AA734BA10" xlink:to="loc_us-gaap_InventoryWorkInProcessNetOfReserves_2930BD877E2A8CFBCC87591AA734F525" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InventoryRawMaterialsAndPurchasedPartsNetOfReserves" xlink:label="loc_us-gaap_InventoryRawMaterialsAndPurchasedPartsNetOfReserves_FBF379667AEFE8794016591AA734BAF7" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryNetItemsNetOfReserveAlternativeAbstract_F9BB87C0E25C14517971591AA734BA10" xlink:to="loc_us-gaap_InventoryRawMaterialsAndPurchasedPartsNetOfReserves_FBF379667AEFE8794016591AA734BAF7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InventorySuppliesNetOfReserves" xlink:label="loc_us-gaap_InventorySuppliesNetOfReserves_165F1FAE1967FD5C6FA6591AA734BFBA" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryNetItemsNetOfReserveAlternativeAbstract_F9BB87C0E25C14517971591AA734BA10" xlink:to="loc_us-gaap_InventorySuppliesNetOfReserves_165F1FAE1967FD5C6FA6591AA734BFBA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet_0386EB4512F762C92F82591AA7343D5D" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InventoryNetItemsNetOfReserveAlternativeAbstract_F9BB87C0E25C14517971591AA734BA10" xlink:to="loc_us-gaap_InventoryNet_0386EB4512F762C92F82591AA7343D5D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LIFOMethodRelatedItemsAbstract" xlink:label="loc_us-gaap_LIFOMethodRelatedItemsAbstract_4016E74A998410069A6D591AA73438F0" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_A74CC07EE45DBEA3956E591AA7346919" xlink:to="loc_us-gaap_LIFOMethodRelatedItemsAbstract_4016E74A998410069A6D591AA73438F0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LIFOInventoryAmount" xlink:label="loc_us-gaap_LIFOInventoryAmount_406AB1882D78B5861978591AA7341E71" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LIFOMethodRelatedItemsAbstract_4016E74A998410069A6D591AA73438F0" xlink:to="loc_us-gaap_LIFOInventoryAmount_406AB1882D78B5861978591AA7341E71" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FIFOInventoryAmount" xlink:label="loc_us-gaap_FIFOInventoryAmount_9CE983020DF2515F2CE8591AA734F6ED" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LIFOMethodRelatedItemsAbstract_4016E74A998410069A6D591AA73438F0" xlink:to="loc_us-gaap_FIFOInventoryAmount_9CE983020DF2515F2CE8591AA734F6ED" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WeightedAverageCostInventoryAmount" xlink:label="loc_us-gaap_WeightedAverageCostInventoryAmount_54F0494C401BDEF4BFDE591AA7348996" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LIFOMethodRelatedItemsAbstract_4016E74A998410069A6D591AA73438F0" xlink:to="loc_us-gaap_WeightedAverageCostInventoryAmount_54F0494C401BDEF4BFDE591AA7348996" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ExcessOfReplacementOrCurrentCostsOverStatedLIFOValue" xlink:label="loc_us-gaap_ExcessOfReplacementOrCurrentCostsOverStatedLIFOValue_2D6BDDF2312BD8B2C067591AA73433A7" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LIFOMethodRelatedItemsAbstract_4016E74A998410069A6D591AA73438F0" xlink:to="loc_us-gaap_ExcessOfReplacementOrCurrentCostsOverStatedLIFOValue_2D6BDDF2312BD8B2C067591AA73433A7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InventoryLIFOReserveEffectOnIncomeNet" xlink:label="loc_us-gaap_InventoryLIFOReserveEffectOnIncomeNet_AEFF1323B76B3C611426591AA734D987" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LIFOMethodRelatedItemsAbstract_4016E74A998410069A6D591AA73438F0" xlink:to="loc_us-gaap_InventoryLIFOReserveEffectOnIncomeNet_AEFF1323B76B3C611426591AA734D987" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProvisionForLossOnContracts" xlink:label="loc_us-gaap_ProvisionForLossOnContracts_D30AA5A78F20ADE0BB3F591AA73421E0" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_A74CC07EE45DBEA3956E591AA7346919" xlink:to="loc_us-gaap_ProvisionForLossOnContracts_D30AA5A78F20ADE0BB3F591AA73421E0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossOnContracts" xlink:label="loc_us-gaap_LossOnContracts_8705B833656A1560B3B5591AA7345C31" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_A74CC07EE45DBEA3956E591AA7346919" xlink:to="loc_us-gaap_LossOnContracts_8705B833656A1560B3B5591AA7345C31" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_1D5E861BFC36C3A11A5C591AA73490A3" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_A74CC07EE45DBEA3956E591AA7346919" xlink:to="loc_us-gaap_Revenues_1D5E861BFC36C3A11A5C591AA73490A3" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_PercentageComplete" xlink:label="loc_hsc_PercentageComplete_B1C48FCCD25465C441A0591AA734EFF3" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_A74CC07EE45DBEA3956E591AA7346919" xlink:to="loc_hsc_PercentageComplete_B1C48FCCD25465C441A0591AA734EFF3" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/AccountsReceivableAndInventoriesTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/AcquisitionsAndDispositions" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/AcquisitionsAndDispositionsAssetsAndLiabilitiesHeldForSaleDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_E172B77299753E11D47A3AA589572503" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_E172B77299753E11D47A3AA589572503" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationAxis" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_3FF5D2FB5259A7BFF9AF3AA589585A92" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_E172B77299753E11D47A3AA589572503" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_3FF5D2FB5259A7BFF9AF3AA589585A92" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_6B08A7BF7830DAA2AFF83AA58958A4E1_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_3FF5D2FB5259A7BFF9AF3AA589585A92" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_6B08A7BF7830DAA2AFF83AA58958A4E1_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_6B08A7BF7830DAA2AFF83AA58958A4E1" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_3FF5D2FB5259A7BFF9AF3AA589585A92" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_6B08A7BF7830DAA2AFF83AA58958A4E1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationsHeldforsaleMember" xlink:label="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember_4C529742D423412657B23AA58958EE68" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_6B08A7BF7830DAA2AFF83AA58958A4E1" xlink:to="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember_4C529742D423412657B23AA58958EE68" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1502D897C0E451FDF89C3AA589582293" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_E172B77299753E11D47A3AA589572503" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1502D897C0E451FDF89C3AA589582293" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_EA884D1F29A913D58EB43AA58959E0E8_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1502D897C0E451FDF89C3AA589582293" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_EA884D1F29A913D58EB43AA58959E0E8_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_EA884D1F29A913D58EB43AA58959E0E8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1502D897C0E451FDF89C3AA589582293" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_EA884D1F29A913D58EB43AA58959E0E8" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoIndustrialMember" xlink:label="loc_hsc_HarscoIndustrialMember_281597464E67982A3CC63AA58959B4DB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_EA884D1F29A913D58EB43AA58959E0E8" xlink:to="loc_hsc_HarscoIndustrialMember_281597464E67982A3CC63AA58959B4DB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsNotesAndLoansReceivableNet" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsNotesAndLoansReceivableNet_8BCD3147A33FC877C8103AA5895B4003" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsNotesAndLoansReceivableNet_8BCD3147A33FC877C8103AA5895B4003" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DisposalGroupIncludingDiscontinuedOperationOtherReceivablesCurrent" xlink:label="loc_hsc_DisposalGroupIncludingDiscontinuedOperationOtherReceivablesCurrent_6331A2315959EA8994453AA5895BC028" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_hsc_DisposalGroupIncludingDiscontinuedOperationOtherReceivablesCurrent_6331A2315959EA8994453AA5895BC028" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationInventoryCurrent" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationInventoryCurrent_2B451480F12E4BC19B163AA5895C4EA9" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationInventoryCurrent_2B451480F12E4BC19B163AA5895C4EA9" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DisposalGroupIncludingDiscontinuedOperationContractWithCustomerAssetNetCurrent" xlink:label="loc_hsc_DisposalGroupIncludingDiscontinuedOperationContractWithCustomerAssetNetCurrent_931AE3CD797A1A0803D23AA5895CB991" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_hsc_DisposalGroupIncludingDiscontinuedOperationContractWithCustomerAssetNetCurrent_931AE3CD797A1A0803D23AA5895CB991" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets_4A8E78B162FD9AD9E12D3AA5895C6E89" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets_4A8E78B162FD9AD9E12D3AA5895C6E89" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent_25B57B0953826350CDDD3AA5895CB26B" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent_25B57B0953826350CDDD3AA5895CB26B" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DisposalGroupIncludingDiscontinuedOperationRightOfUseAssetsNoncurrent" xlink:label="loc_hsc_DisposalGroupIncludingDiscontinuedOperationRightOfUseAssetsNoncurrent_F8AEBD523A0E1AF3C0033AA5895C869F" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_hsc_DisposalGroupIncludingDiscontinuedOperationRightOfUseAssetsNoncurrent_F8AEBD523A0E1AF3C0033AA5895C869F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwillNoncurrent" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwillNoncurrent_986FED3F8660A47FEAF03AA5895CAD7E" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwillNoncurrent_986FED3F8660A47FEAF03AA5895CAD7E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationIntangibleAssetsNoncurrent" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationIntangibleAssetsNoncurrent_6F9C16966237038FDA503AA5895D9BF2" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationIntangibleAssetsNoncurrent_6F9C16966237038FDA503AA5895D9BF2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredTaxAssets" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredTaxAssets_2771FFEED542FCF780DE3AA5895D38D7" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredTaxAssets_2771FFEED542FCF780DE3AA5895D38D7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets_BFEECBBA7697188F30ED3AA5895D66F8" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets_BFEECBBA7697188F30ED3AA5895D66F8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_18826DEF3567E91DE0EC3AA5895DE84D" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_18826DEF3567E91DE0EC3AA5895DE84D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableCurrent" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableCurrent_D8C3E829E0F95DE914EB3AA5895D1E84" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableCurrent_D8C3E829E0F95DE914EB3AA5895D1E84" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccruedLiabilitiesCurrent_10AA3E95FEF98D15D4913AA5895D594D" xlink:type="locator"/>
<link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccruedLiabilitiesCurrent_10AA3E95FEF98D15D4913AA5895D594D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredRevenueCurrent" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredRevenueCurrent_1E5F3F75B24EAE41B6393AA5895E6A49" xlink:type="locator"/>
<link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredRevenueCurrent_1E5F3F75B24EAE41B6393AA5895E6A49" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseLiabilityCurrent" xlink:label="loc_hsc_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseLiabilityCurrent_9380F04D05793F69FC413AA5895EC2F1" xlink:type="locator"/>
<link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_hsc_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseLiabilityCurrent_9380F04D05793F69FC413AA5895EC2F1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentLiabilities" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentLiabilities_B97D5EF32E57A3B28FA13AA5895ECD89" xlink:type="locator"/>
<link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentLiabilities_B97D5EF32E57A3B28FA13AA5895ECD89" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseLiabilityNoncurrent" xlink:label="loc_hsc_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseLiabilityNoncurrent_F46B1E29885E6D6FFE493AA5895EB58E" xlink:type="locator"/>
<link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_hsc_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseLiabilityNoncurrent_F46B1E29885E6D6FFE493AA5895EB58E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities_C03E57DAF38D768EF7353AA5895E2227" xlink:type="locator"/>
<link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities_C03E57DAF38D768EF7353AA5895E2227" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation" xlink:label="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_BC6A578F1E980361CAFC3AA5895ED4B6" xlink:type="locator"/>
<link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ACCB7A03D064B82212E53AA5895BEC43" xlink:to="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_BC6A578F1E980361CAFC3AA5895ED4B6" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/AcquisitionsAndDispositionsNarrativeDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_DE6789626492CD00538F3AE2FD159907" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_DE6789626492CD00538F3AE2FD159907" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NonrecurringAdjustmentAxis" xlink:label="loc_us-gaap_NonrecurringAdjustmentAxis_720D14B30804C3DBD6663AE2FD167BC2" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_DE6789626492CD00538F3AE2FD159907" xlink:to="loc_us-gaap_NonrecurringAdjustmentAxis_720D14B30804C3DBD6663AE2FD167BC2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NonrecurringAdjustmentDomain" xlink:label="loc_us-gaap_NonrecurringAdjustmentDomain_712DCC3B30640E869AEB3AE2FD16B710_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_NonrecurringAdjustmentAxis_720D14B30804C3DBD6663AE2FD167BC2" xlink:to="loc_us-gaap_NonrecurringAdjustmentDomain_712DCC3B30640E869AEB3AE2FD16B710_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NonrecurringAdjustmentDomain" xlink:label="loc_us-gaap_NonrecurringAdjustmentDomain_712DCC3B30640E869AEB3AE2FD16B710" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_NonrecurringAdjustmentAxis_720D14B30804C3DBD6663AE2FD167BC2" xlink:to="loc_us-gaap_NonrecurringAdjustmentDomain_712DCC3B30640E869AEB3AE2FD16B710" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AcquisitionRelatedCostsMember" xlink:label="loc_us-gaap_AcquisitionRelatedCostsMember_D9C02AA886E74516DC003AE2FD16FCA9" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonrecurringAdjustmentDomain_712DCC3B30640E869AEB3AE2FD16B710" xlink:to="loc_us-gaap_AcquisitionRelatedCostsMember_D9C02AA886E74516DC003AE2FD16FCA9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_6F363A2A7FDFEDB422C33AE2FD17FD35" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_DE6789626492CD00538F3AE2FD159907" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_6F363A2A7FDFEDB422C33AE2FD17FD35" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_9F17DA811BBB463EF5F33AE2FD177825_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_6F363A2A7FDFEDB422C33AE2FD17FD35" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_9F17DA811BBB463EF5F33AE2FD177825_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_9F17DA811BBB463EF5F33AE2FD177825" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_6F363A2A7FDFEDB422C33AE2FD17FD35" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_9F17DA811BBB463EF5F33AE2FD177825" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_03748754E932C80C29AE3AE2FD17190E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_9F17DA811BBB463EF5F33AE2FD177825" xlink:to="loc_us-gaap_SubsequentEventMember_03748754E932C80C29AE3AE2FD17190E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_063EAF6D85FF40D6C4C23AE2FD17BD80" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_DE6789626492CD00538F3AE2FD159907" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_063EAF6D85FF40D6C4C23AE2FD17BD80" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6C0F0F5B94CF75B734403AE2FD18F69D_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_063EAF6D85FF40D6C4C23AE2FD17BD80" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6C0F0F5B94CF75B734403AE2FD18F69D_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6C0F0F5B94CF75B734403AE2FD18F69D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_063EAF6D85FF40D6C4C23AE2FD17BD80" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6C0F0F5B94CF75B734403AE2FD18F69D" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoIndustrialMember" xlink:label="loc_hsc_HarscoIndustrialMember_93757E896A1A3FBC4AF23AE2FD18A26A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6C0F0F5B94CF75B734403AE2FD18F69D" xlink:to="loc_hsc_HarscoIndustrialMember_93757E896A1A3FBC4AF23AE2FD18A26A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoIndustrialPattersonKelleyMember" xlink:label="loc_hsc_HarscoIndustrialPattersonKelleyMember_56722162363E0F919FEA3AE2FD187530" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6C0F0F5B94CF75B734403AE2FD18F69D" xlink:to="loc_hsc_HarscoIndustrialPattersonKelleyMember_56722162363E0F919FEA3AE2FD187530" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoIndustrialIKGMember" xlink:label="loc_hsc_HarscoIndustrialIKGMember_1F328ED947A1127742783AE2FD184EB5" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6C0F0F5B94CF75B734403AE2FD18F69D" xlink:to="loc_hsc_HarscoIndustrialIKGMember_1F328ED947A1127742783AE2FD184EB5" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoIndustrialAirXChangersBusinessMember" xlink:label="loc_hsc_HarscoIndustrialAirXChangersBusinessMember_BED67379613390B92C263AE2FD1969CA" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6C0F0F5B94CF75B734403AE2FD18F69D" xlink:to="loc_hsc_HarscoIndustrialAirXChangersBusinessMember_BED67379613390B92C263AE2FD1969CA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationAxis" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_07377CE99B6AC26D4EF23AE2FD1953A2" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_DE6789626492CD00538F3AE2FD159907" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_07377CE99B6AC26D4EF23AE2FD1953A2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_F0E5021FED258860B22F3AE2FD192CF2_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_07377CE99B6AC26D4EF23AE2FD1953A2" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_F0E5021FED258860B22F3AE2FD192CF2_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_F0E5021FED258860B22F3AE2FD192CF2" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_07377CE99B6AC26D4EF23AE2FD1953A2" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_F0E5021FED258860B22F3AE2FD192CF2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationsHeldforsaleMember" xlink:label="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember_9C9935E66E2D146DBF313AE2FD1924E6" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_F0E5021FED258860B22F3AE2FD192CF2" xlink:to="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember_9C9935E66E2D146DBF313AE2FD1924E6" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_146B8181372B42F879633AE2FD1A226A" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_F0E5021FED258860B22F3AE2FD192CF2" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_146B8181372B42F879633AE2FD1A226A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_F182F82875AA64AD44D33AE2FD1ACD4D" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_DE6789626492CD00538F3AE2FD159907" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_F182F82875AA64AD44D33AE2FD1ACD4D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C79FDD16D97E98046CDE3AE2FD1AFBEE_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_F182F82875AA64AD44D33AE2FD1ACD4D" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C79FDD16D97E98046CDE3AE2FD1AFBEE_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C79FDD16D97E98046CDE3AE2FD1AFBEE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_F182F82875AA64AD44D33AE2FD1ACD4D" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C79FDD16D97E98046CDE3AE2FD1AFBEE" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_62C3DF4F1A59079EBEE53AE2FD1A4E5C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C79FDD16D97E98046CDE3AE2FD1AFBEE" xlink:to="loc_hsc_CleanEarthMember_62C3DF4F1A59079EBEE53AE2FD1A4E5C" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AltekGroupMember" xlink:label="loc_hsc_AltekGroupMember_F6C9CA0544D49716C3233AE2FD1BE253" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C79FDD16D97E98046CDE3AE2FD1AFBEE" xlink:to="loc_hsc_AltekGroupMember_F6C9CA0544D49716C3233AE2FD1BE253" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_7789512D2B11F1ECED9B3AE2FD1B05CE" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_DE6789626492CD00538F3AE2FD159907" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_7789512D2B11F1ECED9B3AE2FD1B05CE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_B091BEC53F7FC90D147C3AE2FD1BE4FA_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_7789512D2B11F1ECED9B3AE2FD1B05CE" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_B091BEC53F7FC90D147C3AE2FD1BE4FA_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_B091BEC53F7FC90D147C3AE2FD1BE4FA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_7789512D2B11F1ECED9B3AE2FD1B05CE" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_B091BEC53F7FC90D147C3AE2FD1BE4FA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_F715D499DEB16B96B3703AE2FD1BF4CA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_F715D499DEB16B96B3703AE2FD1BF4CA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_292244385D74E630F94A3AE2FD1CC04C" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_292244385D74E630F94A3AE2FD1CC04C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_2323E38C6B3D28CAA9683AE2FD1C5384" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_2323E38C6B3D28CAA9683AE2FD1C5384" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationContingentConsiderationArrangementsPostClosingPeriod" xlink:label="loc_hsc_BusinessCombinationContingentConsiderationArrangementsPostClosingPeriod_325158F408B9FB3411DE3AE2FD1C7F5E" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_hsc_BusinessCombinationContingentConsiderationArrangementsPostClosingPeriod_325158F408B9FB3411DE3AE2FD1C7F5E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_B5A4A372B6FA9CFD5F953AE2FD1CF832" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_B5A4A372B6FA9CFD5F953AE2FD1CF832" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NumberOfStores" xlink:label="loc_us-gaap_NumberOfStores_420703D2ED20E37949623AE2FD1C336B" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_NumberOfStores_420703D2ED20E37949623AE2FD1C336B" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_NumberOfPermitsAcquired" xlink:label="loc_hsc_NumberOfPermitsAcquired_6115F9888FB44CC3E0D73AE2FD1D0939" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_hsc_NumberOfPermitsAcquired_6115F9888FB44CC3E0D73AE2FD1D0939" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount" xlink:label="loc_us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount_2E1E387587307EDB04483AE2FD1D9629" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount_2E1E387587307EDB04483AE2FD1D9629" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_F96991B4FF5A0AD1D59C3AE2FD1DD9DC" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_F96991B4FF5A0AD1D59C3AE2FD1DD9DC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_0F710D147FE0D0BC355A3AE2FD1D773E" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_InterestExpense_0F710D147FE0D0BC355A3AE2FD1D773E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_2920685AA13C4F2DD2143AE2FD1DF037" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_2920685AA13C4F2DD2143AE2FD1DF037" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh_8A8AF14F6425997D26273AE2FD1D3657" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh_8A8AF14F6425997D26273AE2FD1D3657" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_3241590AA7AC50620DCC3AE2FD1EDD91" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_3241590AA7AC50620DCC3AE2FD1EDD91" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DisposalGroupNetGainonDisposalAfterTax" xlink:label="loc_hsc_DisposalGroupNetGainonDisposalAfterTax_2334E8FEFE5CC41CA0933AE2FD1E3808" xlink:type="locator"/>
<link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_hsc_DisposalGroupNetGainonDisposalAfterTax_2334E8FEFE5CC41CA0933AE2FD1E3808" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DisposalGroupNetGainonDisposal" xlink:label="loc_hsc_DisposalGroupNetGainonDisposal_DB055E9A71DFAB1F3C893AE2FD1E942C" xlink:type="locator"/>
<link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_hsc_DisposalGroupNetGainonDisposal_DB055E9A71DFAB1F3C893AE2FD1E942C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromDivestitureOfBusinesses" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_E4166D3D8FB2C5F9665E3AE2FD1E3EBB" xlink:type="locator"/>
<link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_E4166D3D8FB2C5F9665E3AE2FD1E3EBB" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DisposalGroupIncludingDiscontinuedOperationCorporateOverhead" xlink:label="loc_hsc_DisposalGroupIncludingDiscontinuedOperationCorporateOverhead_98D1D09ECBB0830141A03AE2FD1EBA90" xlink:type="locator"/>
<link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FB46C44C850A6ED891323AE2FD1B29F3" xlink:to="loc_hsc_DisposalGroupIncludingDiscontinuedOperationCorporateOverhead_98D1D09ECBB0830141A03AE2FD1EBA90" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/AcquisitionsAndDispositionsProFormaInformationDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_FD8DF0CC17FE4AD08ED8591AA7650F88" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_8FF0D17BCDB672529254591AA7653346" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FD8DF0CC17FE4AD08ED8591AA7650F88" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_8FF0D17BCDB672529254591AA7653346" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_F98EB3634A710A7B7EC5591AA765148C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_8FF0D17BCDB672529254591AA7653346" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_F98EB3634A710A7B7EC5591AA765148C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_124149E02F8EBE88AAF0591AA7655965_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_F98EB3634A710A7B7EC5591AA765148C" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_124149E02F8EBE88AAF0591AA7655965_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_124149E02F8EBE88AAF0591AA7655965" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_F98EB3634A710A7B7EC5591AA765148C" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_124149E02F8EBE88AAF0591AA7655965" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_CEEA4D879E9DE16CBA4F591AA7651987" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_124149E02F8EBE88AAF0591AA7655965" xlink:to="loc_hsc_CleanEarthMember_CEEA4D879E9DE16CBA4F591AA7651987" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaRevenue" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_3436E335C8902891FCFB591AA765DE54" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FD8DF0CC17FE4AD08ED8591AA7650F88" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_3436E335C8902891FCFB591AA765DE54" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_8713E34898D0933BE623591AA76570B2" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FD8DF0CC17FE4AD08ED8591AA7650F88" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_8713E34898D0933BE623591AA76570B2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainLossOnSaleOfBusiness" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_412BDA05653DD047F39A591AA765F4D3" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FD8DF0CC17FE4AD08ED8591AA7650F88" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_412BDA05653DD047F39A591AA765F4D3" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/AcquisitionsAndDispositionsSummaryOfAssetsAcquiredAndLiabilitiesAssumedDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_583BD7BA1B557E562D125993E473E6AA" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_768CBE8107252A6CA4905993E4709779" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_583BD7BA1B557E562D125993E473E6AA" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_768CBE8107252A6CA4905993E4709779" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_70274F190C205C76F2505993E4702994" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_768CBE8107252A6CA4905993E4709779" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_70274F190C205C76F2505993E4702994" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_F1324AACB3410B4DFFF35993E4709760_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_70274F190C205C76F2505993E4702994" xlink:to="loc_us-gaap_SegmentDomain_F1324AACB3410B4DFFF35993E4709760_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_F1324AACB3410B4DFFF35993E4709760" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_70274F190C205C76F2505993E4702994" xlink:to="loc_us-gaap_SegmentDomain_F1324AACB3410B4DFFF35993E4709760" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_CB57D98FD5449994C1325993E4718E6C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_F1324AACB3410B4DFFF35993E4709760" xlink:to="loc_hsc_CleanEarthMember_CB57D98FD5449994C1325993E4718E6C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_B3338788FA0F7B8BBC185993E4716A7A" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_768CBE8107252A6CA4905993E4709779" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_B3338788FA0F7B8BBC185993E4716A7A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_7D665FC321920D531E225993E4712BB5_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_B3338788FA0F7B8BBC185993E4716A7A" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_7D665FC321920D531E225993E4712BB5_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_7D665FC321920D531E225993E4712BB5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_B3338788FA0F7B8BBC185993E4716A7A" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_7D665FC321920D531E225993E4712BB5" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoIndustrialMember" xlink:label="loc_hsc_HarscoIndustrialMember_AE70BED4B774A711D7BE5993E4714CAB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_7D665FC321920D531E225993E4712BB5" xlink:to="loc_hsc_HarscoIndustrialMember_AE70BED4B774A711D7BE5993E4714CAB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationAxis" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_249E13DA43FB920F404A5993E472CBC2" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_768CBE8107252A6CA4905993E4709779" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_249E13DA43FB920F404A5993E472CBC2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_54295B8A11BAE6FAE1255993E4723636_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_249E13DA43FB920F404A5993E472CBC2" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_54295B8A11BAE6FAE1255993E4723636_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_54295B8A11BAE6FAE1255993E4723636" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_249E13DA43FB920F404A5993E472CBC2" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_54295B8A11BAE6FAE1255993E4723636" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationsHeldforsaleMember" xlink:label="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember_561ADEF32B88B7E72F465993E472864A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_54295B8A11BAE6FAE1255993E4723636" xlink:to="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember_561ADEF32B88B7E72F465993E472864A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_5A345BAC84B24CAE223A5993E473FC28" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_768CBE8107252A6CA4905993E4709779" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_5A345BAC84B24CAE223A5993E473FC28" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_E31EC786C1558162388A5993E4736F29_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_5A345BAC84B24CAE223A5993E473FC28" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_E31EC786C1558162388A5993E4736F29_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_E31EC786C1558162388A5993E4736F29" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_5A345BAC84B24CAE223A5993E473FC28" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_E31EC786C1558162388A5993E4736F29" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_7BD46FB819B6F871F76F5993E473DB5E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_E31EC786C1558162388A5993E4736F29" xlink:to="loc_hsc_CleanEarthMember_7BD46FB819B6F871F76F5993E473DB5E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AltekGroupMember" xlink:label="loc_hsc_AltekGroupMember_D15FB33C93ACD2F39A445993E4736ADA" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_E31EC786C1558162388A5993E4736F29" xlink:to="loc_hsc_AltekGroupMember_D15FB33C93ACD2F39A445993E4736ADA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_583BD7BA1B557E562D125993E473E6AA" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_D705A0F13B0F64E991735993E474567A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_D705A0F13B0F64E991735993E474567A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentAssetsLiabilitiesNet" xlink:label="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentAssetsLiabilitiesNet_13C00510ACA3F7E5BB405993E4741519" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentAssetsLiabilitiesNet_13C00510ACA3F7E5BB405993E4741519" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_914FD6B99FBEE1DDF95F5993E4742BFE" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_914FD6B99FBEE1DDF95F5993E4742BFE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_A411EA6B94D2B3BDD7E45993E475F7E7" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_A411EA6B94D2B3BDD7E45993E475F7E7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_D5A3FECA11EA8F0CCA245993E4750BE4" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_Goodwill_D5A3FECA11EA8F0CCA245993E4750BE4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_3FF911AE57E16F6278A45993E475CA99" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_3FF911AE57E16F6278A45993E475CA99" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesOther" xlink:label="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesOther_71ED28B36482419888A15993E475AACA" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesOther_71ED28B36482419888A15993E475AACA" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsTradeReceivables" xlink:label="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsTradeReceivables_DF2B9DCF36CAEAD2B6A95993E475EE95" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsTradeReceivables_DF2B9DCF36CAEAD2B6A95993E475EE95" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOtherReceivables" xlink:label="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOtherReceivables_EF07E9DF17212381FA855993E475CB67" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOtherReceivables_EF07E9DF17212381FA855993E475CB67" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_43332DF96DB76A18283C5993E4763527" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_43332DF96DB76A18283C5993E4763527" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightofUseAsset" xlink:label="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightofUseAsset_D76A0C33B6CA5091A7E45993E47654EC" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingLeaseRightofUseAsset_D76A0C33B6CA5091A7E45993E47654EC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_063AFCFB019149B6BDA15993E4762FA4" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_063AFCFB019149B6BDA15993E4762FA4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_BAF431FEB41DCCBDCBCE5993E476916C" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_BAF431FEB41DCCBDCBCE5993E476916C" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAccountsPayable" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAccountsPayable_AEB918A0DCA068F310D25993E4766F52" xlink:type="locator"/>
<link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAccountsPayable_AEB918A0DCA068F310D25993E4766F52" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAcquisitionConsiderationPayable" xlink:label="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAcquisitionConsiderationPayable_6E9E7D9C529C09BA51805993E47644C1" xlink:type="locator"/>
<link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_hsc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAcquisitionConsiderationPayable_6E9E7D9C529C09BA51805993E47644C1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther_29BFE410C7578D8270B25993E47626BE" xlink:type="locator"/>
<link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther_29BFE410C7578D8270B25993E47626BE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation_EF15B182153D7F874AE95993E477D6FF" xlink:type="locator"/>
<link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation_EF15B182153D7F874AE95993E477D6FF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_C294C2FB0693AD43EC3D5993E47750BD" xlink:type="locator"/>
<link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_C294C2FB0693AD43EC3D5993E47750BD" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_2691A8E2D2E88C3C86455993E477A32F" xlink:type="locator"/>
<link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract_71361E55901B6EE0EACA5993E474972E" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_2691A8E2D2E88C3C86455993E477A32F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_583BD7BA1B557E562D125993E473E6AA" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCash" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCash_0731D99570D4ABB64CA35993E477CB91" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCash_0731D99570D4ABB64CA35993E477CB91" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustment" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustment_98F3D54DA5FE8AB22B285993E478251F" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustment_98F3D54DA5FE8AB22B285993E478251F" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherReceivables" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherReceivables_5ADF4D78C2D47AE45A115993E478A09C" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherReceivables_5ADF4D78C2D47AE45A115993E478A09C" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherCurrentAssets" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherCurrentAssets_105AEE50AFB71C72A42B5993E4783BB5" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherCurrentAssets_105AEE50AFB71C72A42B5993E4783BB5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment_6EDC4EF79D2B1BD35DCC5993E478F694" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment_6EDC4EF79D2B1BD35DCC5993E478F694" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentRightofUseAsset" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentRightofUseAsset_8F8D1743D5EE27C5473A5993E478619C" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentRightofUseAsset_8F8D1743D5EE27C5473A5993E478619C" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherAssets" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherAssets_D08ECF470CA7EC99FF205993E479B885" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherAssets_D08ECF470CA7EC99FF205993E479B885" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAcquisitionConsiderationPayable" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAcquisitionConsiderationPayable_0876EB39B3BAFA9C8F465993E4791F1A" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAcquisitionConsiderationPayable_0876EB39B3BAFA9C8F465993E4791F1A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherCurrentLiabilities" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherCurrentLiabilities_33B3B191CE20871E8CFE5993E479B839" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherCurrentLiabilities_33B3B191CE20871E8CFE5993E479B839" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentNetdeferredTaxesLiability" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentNetdeferredTaxesLiability_9534BF5A6981B4EC99AD5993E4792211" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentNetdeferredTaxesLiability_9534BF5A6981B4EC99AD5993E4792211" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOperatingleaseliabilities" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOperatingleaseliabilities_B8F612746712C968006D5993E4797661" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOperatingleaseliabilities_B8F612746712C968006D5993E4797661" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherLiabilities" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherLiabilities_0438B741AC8DCE666FFB5993E4797409" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherLiabilities_0438B741AC8DCE666FFB5993E4797409" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCurrentAssetsLiabilitiesNet" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCurrentAssetsLiabilitiesNet_35CDA7B9597EB56C7C975993E4794376" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCurrentAssetsLiabilitiesNet_35CDA7B9597EB56C7C975993E4794376" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_95B47894A99C377420C75993E47A04A8" xlink:type="locator"/>
<link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_95B47894A99C377420C75993E47A04A8" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentGoodwill" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentGoodwill_53ADFE8DBB72AC34FBE15993E47A3B01" xlink:type="locator"/>
<link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentGoodwill_53ADFE8DBB72AC34FBE15993E47A3B01" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentConsiderationTransferred" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentConsiderationTransferred_CA7A08C6F48C42FE3E1C5993E47A83AB" xlink:type="locator"/>
<link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsAbstract_47EE68839969AC8ADD715993E477CA65" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentConsiderationTransferred_CA7A08C6F48C42FE3E1C5993E47A83AB" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/AcquisitionsAndDispositionsSummaryOfCashFlowInformationDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_5F56FE96B855129F8E1B3AA5898CCE00" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3A5F0145CC678B0448663AA58988A52E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5F56FE96B855129F8E1B3AA5898CCE00" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3A5F0145CC678B0448663AA58988A52E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationAxis" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_1CE138D092E2B69D90043AA58988EAC9" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3A5F0145CC678B0448663AA58988A52E" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_1CE138D092E2B69D90043AA58988EAC9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_DCB1C659CAE47C4909133AA58989D42D_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_1CE138D092E2B69D90043AA58988EAC9" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_DCB1C659CAE47C4909133AA58989D42D_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_DCB1C659CAE47C4909133AA58989D42D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_1CE138D092E2B69D90043AA58988EAC9" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_DCB1C659CAE47C4909133AA58989D42D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationsHeldforsaleMember" xlink:label="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember_2719399D72368BEA219A3AA5898970F5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_DCB1C659CAE47C4909133AA58989D42D" xlink:to="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember_2719399D72368BEA219A3AA5898970F5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_B14BFDCDE077992205663AA58989ED0E" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3A5F0145CC678B0448663AA58988A52E" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_B14BFDCDE077992205663AA58989ED0E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_8839FCBC71451CD1E5E33AA58989B247_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_B14BFDCDE077992205663AA58989ED0E" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_8839FCBC71451CD1E5E33AA58989B247_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_8839FCBC71451CD1E5E33AA58989B247" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_B14BFDCDE077992205663AA58989ED0E" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_8839FCBC71451CD1E5E33AA58989B247" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoIndustrialMember" xlink:label="loc_hsc_HarscoIndustrialMember_EBD202E19AC2B3ADFAE53AA5898A534A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_8839FCBC71451CD1E5E33AA58989B247" xlink:to="loc_hsc_HarscoIndustrialMember_EBD202E19AC2B3ADFAE53AA5898A534A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DepreciationAndAmortizationDiscontinuedOperations" xlink:label="loc_us-gaap_DepreciationAndAmortizationDiscontinuedOperations_A04FB7583B89C8D1D6923AA5898C4466" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5F56FE96B855129F8E1B3AA5898CCE00" xlink:to="loc_us-gaap_DepreciationAndAmortizationDiscontinuedOperations_A04FB7583B89C8D1D6923AA5898C4466" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalExpenditureDiscontinuedOperations" xlink:label="loc_us-gaap_CapitalExpenditureDiscontinuedOperations_62E862262D856460C0673AA5898CC793" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5F56FE96B855129F8E1B3AA5898CCE00" xlink:to="loc_us-gaap_CapitalExpenditureDiscontinuedOperations_62E862262D856460C0673AA5898CC793" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/AcquisitionsAndDispositionsSummaryOfChangesInFairValueOfContingentConsiderationDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_3030B9FF94845799DB6B3AE2FCE23D1C" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_61B2F109A02B49E9748D3AE2FCE1D5AD" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3030B9FF94845799DB6B3AE2FCE23D1C" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_61B2F109A02B49E9748D3AE2FCE1D5AD" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_5142C199F74A97C5E8C93AE2FCE1AE18" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_61B2F109A02B49E9748D3AE2FCE1D5AD" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_5142C199F74A97C5E8C93AE2FCE1AE18" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_B0C8E6EB52D32B4F55BB3AE2FCE2F5E2_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_5142C199F74A97C5E8C93AE2FCE1AE18" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_B0C8E6EB52D32B4F55BB3AE2FCE2F5E2_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_B0C8E6EB52D32B4F55BB3AE2FCE2F5E2" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_5142C199F74A97C5E8C93AE2FCE1AE18" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_B0C8E6EB52D32B4F55BB3AE2FCE2F5E2" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AltekGroupMember" xlink:label="loc_hsc_AltekGroupMember_44F4C25C3E6A5326B0C93AE2FCE2C6FF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_B0C8E6EB52D32B4F55BB3AE2FCE2F5E2" xlink:to="loc_hsc_AltekGroupMember_44F4C25C3E6A5326B0C93AE2FCE2C6FF" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationContingentConsiderationLiabilityRollForward" xlink:label="loc_hsc_BusinessCombinationContingentConsiderationLiabilityRollForward_139548760D5ADBD6895C3AE2FCE225D8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3030B9FF94845799DB6B3AE2FCE23D1C" xlink:to="loc_hsc_BusinessCombinationContingentConsiderationLiabilityRollForward_139548760D5ADBD6895C3AE2FCE225D8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent_EFF540F29BDE0FAF4C3B3AE2FCE345FF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_BusinessCombinationContingentConsiderationLiabilityRollForward_139548760D5ADBD6895C3AE2FCE225D8" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent_EFF540F29BDE0FAF4C3B3AE2FCE345FF" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationContingentConsiderationArrangementsRecognitionOfContingentConsideration" xlink:label="loc_hsc_BusinessCombinationContingentConsiderationArrangementsRecognitionOfContingentConsideration_B47E7CA32DACEC9586853AE2FCE3D24D" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_BusinessCombinationContingentConsiderationLiabilityRollForward_139548760D5ADBD6895C3AE2FCE225D8" xlink:to="loc_hsc_BusinessCombinationContingentConsiderationArrangementsRecognitionOfContingentConsideration_B47E7CA32DACEC9586853AE2FCE3D24D" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationMeasurementPeriodAdjustment" xlink:label="loc_hsc_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationMeasurementPeriodAdjustment_60447B953005917714433AE2FCE3C39A" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_BusinessCombinationContingentConsiderationLiabilityRollForward_139548760D5ADBD6895C3AE2FCE225D8" xlink:to="loc_hsc_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationMeasurementPeriodAdjustment_60447B953005917714433AE2FCE3C39A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationContingentConsiderationArrangementsLiabilityPayments" xlink:label="loc_hsc_BusinessCombinationContingentConsiderationArrangementsLiabilityPayments_973395B5EAFA7F615B5A3AE2FCE34A8E" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_BusinessCombinationContingentConsiderationLiabilityRollForward_139548760D5ADBD6895C3AE2FCE225D8" xlink:to="loc_hsc_BusinessCombinationContingentConsiderationArrangementsLiabilityPayments_973395B5EAFA7F615B5A3AE2FCE34A8E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1_9C86D22BF70E836F82CA3AE2FCE4DED8" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_BusinessCombinationContingentConsiderationLiabilityRollForward_139548760D5ADBD6895C3AE2FCE225D8" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1_9C86D22BF70E836F82CA3AE2FCE4DED8" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationForeignCurrencyTranslation" xlink:label="loc_hsc_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationForeignCurrencyTranslation_869F1289CEDF294884253AE2FCE41ED5" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_BusinessCombinationContingentConsiderationLiabilityRollForward_139548760D5ADBD6895C3AE2FCE225D8" xlink:to="loc_hsc_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationForeignCurrencyTranslation_869F1289CEDF294884253AE2FCE41ED5" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/AcquisitionsAndDispositionsSummaryOfIntangibleAssetsAndAmortizationPeriodsDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_DE5ECE3905E8EA47B08A3AE2FCEC5248" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAcquiredAsPartOfBusinessCombinationTable" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAcquiredAsPartOfBusinessCombinationTable_3C2B94D94BA4583FE1D23AE2FCE92CF3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_DE5ECE3905E8EA47B08A3AE2FCEC5248" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAcquiredAsPartOfBusinessCombinationTable_3C2B94D94BA4583FE1D23AE2FCE92CF3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_FC96D0DC9E2962E7332B3AE2FCEA3C45" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAcquiredAsPartOfBusinessCombinationTable_3C2B94D94BA4583FE1D23AE2FCE92CF3" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_FC96D0DC9E2962E7332B3AE2FCEA3C45" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_F2E35FE04A12A48150463AE2FCEAE513_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_FC96D0DC9E2962E7332B3AE2FCEA3C45" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_F2E35FE04A12A48150463AE2FCEAE513_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_F2E35FE04A12A48150463AE2FCEAE513" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_FC96D0DC9E2962E7332B3AE2FCEA3C45" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_F2E35FE04A12A48150463AE2FCEAE513" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_0AD95BFCA69A3FD054C73AE2FCEA489A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_F2E35FE04A12A48150463AE2FCEAE513" xlink:to="loc_hsc_CleanEarthMember_0AD95BFCA69A3FD054C73AE2FCEA489A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_FB7849FA596B700FE6E93AE2FCEA5373" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAcquiredAsPartOfBusinessCombinationTable_3C2B94D94BA4583FE1D23AE2FCE92CF3" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_FB7849FA596B700FE6E93AE2FCEA5373" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_A22A7DDDD3CA75E44BD43AE2FCEA4D48_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_FB7849FA596B700FE6E93AE2FCEA5373" xlink:to="loc_us-gaap_SegmentDomain_A22A7DDDD3CA75E44BD43AE2FCEA4D48_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_A22A7DDDD3CA75E44BD43AE2FCEA4D48" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_FB7849FA596B700FE6E93AE2FCEA5373" xlink:to="loc_us-gaap_SegmentDomain_A22A7DDDD3CA75E44BD43AE2FCEA4D48" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_0E0DEABF3715CC2F74C93AE2FCEA1CF7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_A22A7DDDD3CA75E44BD43AE2FCEA4D48" xlink:to="loc_hsc_CleanEarthMember_0E0DEABF3715CC2F74C93AE2FCEA1CF7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3907FBDF302FC301D2D03AE2FCEA7DE0" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAcquiredAsPartOfBusinessCombinationTable_3C2B94D94BA4583FE1D23AE2FCE92CF3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3907FBDF302FC301D2D03AE2FCEA7DE0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5A6FEF0FD03A567711E03AE2FCEB0355_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3907FBDF302FC301D2D03AE2FCEA7DE0" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5A6FEF0FD03A567711E03AE2FCEB0355_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5A6FEF0FD03A567711E03AE2FCEB0355" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3907FBDF302FC301D2D03AE2FCEA7DE0" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5A6FEF0FD03A567711E03AE2FCEB0355" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_PermitsAndRightsMember" xlink:label="loc_hsc_PermitsAndRightsMember_E9C7DBA88D83C59C2FA03AE2FCEB0730" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5A6FEF0FD03A567711E03AE2FCEB0355" xlink:to="loc_hsc_PermitsAndRightsMember_E9C7DBA88D83C59C2FA03AE2FCEB0730" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="loc_us-gaap_CustomerRelationshipsMember_17149B31D682743F2F973AE2FCEB199E" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5A6FEF0FD03A567711E03AE2FCEB0355" xlink:to="loc_us-gaap_CustomerRelationshipsMember_17149B31D682743F2F973AE2FCEB199E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AirRightsMember" xlink:label="loc_hsc_AirRightsMember_BABDEB04DFAFF9B2ADE43AE2FCEBBAAA" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5A6FEF0FD03A567711E03AE2FCEB0355" xlink:to="loc_hsc_AirRightsMember_BABDEB04DFAFF9B2ADE43AE2FCEBBAAA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TradeNamesMember" xlink:label="loc_us-gaap_TradeNamesMember_FECF2D8709EF5A6F914F3AE2FCEC7843" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_5A6FEF0FD03A567711E03AE2FCEB0355" xlink:to="loc_us-gaap_TradeNamesMember_FECF2D8709EF5A6F914F3AE2FCEC7843" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_099C459632E86BCF6B863AE2FCEC950B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_DE5ECE3905E8EA47B08A3AE2FCEC5248" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_099C459632E86BCF6B863AE2FCEC950B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_0CFECA1B385CE2F7FC2C3AE2FCEC6237" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_DE5ECE3905E8EA47B08A3AE2FCEC5248" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_0CFECA1B385CE2F7FC2C3AE2FCEC6237" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCustomerRelationships" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCustomerRelationships_294957837A66F85A2BE23AE2FCEC7647" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_DE5ECE3905E8EA47B08A3AE2FCEC5248" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentCustomerRelationships_294957837A66F85A2BE23AE2FCEC7647" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPermits" xlink:label="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPermits_3721B7EBA5C23724B93C3AE2FCEDAFC7" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_DE5ECE3905E8EA47B08A3AE2FCEC5248" xlink:to="loc_hsc_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPermits_3721B7EBA5C23724B93C3AE2FCEDAFC7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_8F4A19937C73A4D114493AE2FCED037C" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_DE5ECE3905E8EA47B08A3AE2FCEC5248" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_8F4A19937C73A4D114493AE2FCED037C" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/AcquisitionsAndDispositionsSummaryOfKeyFinancialInformationDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_1869B62D08D6C1C2FC203AE2FCC4F141" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_D563B5EA1FE96F80A4293AE2FCC02AAF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1869B62D08D6C1C2FC203AE2FCC4F141" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_D563B5EA1FE96F80A4293AE2FCC02AAF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_2C64BA122B2C780F6E873AE2FCC090AF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_D563B5EA1FE96F80A4293AE2FCC02AAF" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_2C64BA122B2C780F6E873AE2FCC090AF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_FAC7D4FDDDE2A960EEDA3AE2FCC1A338_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_2C64BA122B2C780F6E873AE2FCC090AF" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_FAC7D4FDDDE2A960EEDA3AE2FCC1A338_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_FAC7D4FDDDE2A960EEDA3AE2FCC1A338" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_2C64BA122B2C780F6E873AE2FCC090AF" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_FAC7D4FDDDE2A960EEDA3AE2FCC1A338" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="loc_us-gaap_InterestRateSwapMember_295BE9A3B59176AF47143AE2FCC1FF82" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_FAC7D4FDDDE2A960EEDA3AE2FCC1A338" xlink:to="loc_us-gaap_InterestRateSwapMember_295BE9A3B59176AF47143AE2FCC1FF82" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_007195077DFB280697E13AE2FCC19A11" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_D563B5EA1FE96F80A4293AE2FCC02AAF" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_007195077DFB280697E13AE2FCC19A11" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_09AA0769D316624E258D3AE2FCC12D65_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_007195077DFB280697E13AE2FCC19A11" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_09AA0769D316624E258D3AE2FCC12D65_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_09AA0769D316624E258D3AE2FCC12D65" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_007195077DFB280697E13AE2FCC19A11" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_09AA0769D316624E258D3AE2FCC12D65" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AirCooledHeatExchangersMember" xlink:label="loc_hsc_AirCooledHeatExchangersMember_19C3AB147B5DC03B3FFD3AE2FCC2812D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_09AA0769D316624E258D3AE2FCC12D65" xlink:to="loc_hsc_AirCooledHeatExchangersMember_19C3AB147B5DC03B3FFD3AE2FCC2812D" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoIndustrialMember" xlink:label="loc_hsc_HarscoIndustrialMember_029B939A1062990CF5173AE2FCC2230B" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_09AA0769D316624E258D3AE2FCC12D65" xlink:to="loc_hsc_HarscoIndustrialMember_029B939A1062990CF5173AE2FCC2230B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationAxis" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_AA87A8171519AD34C8D13AE2FCC2A43E" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_D563B5EA1FE96F80A4293AE2FCC02AAF" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_AA87A8171519AD34C8D13AE2FCC2A43E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_C657FEBD39A678D255F83AE2FCC2DAEB_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_AA87A8171519AD34C8D13AE2FCC2A43E" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_C657FEBD39A678D255F83AE2FCC2DAEB_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_C657FEBD39A678D255F83AE2FCC2DAEB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_AA87A8171519AD34C8D13AE2FCC2A43E" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_C657FEBD39A678D255F83AE2FCC2DAEB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationsHeldforsaleMember" xlink:label="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember_FFE7646B5EC0F6C0528C3AE2FCC316A2" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_C657FEBD39A678D255F83AE2FCC2DAEB" xlink:to="loc_us-gaap_DiscontinuedOperationsHeldforsaleMember_FFE7646B5EC0F6C0528C3AE2FCC316A2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_15C8BB4E62DB7B200DAC3AE2FCC3C80B" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_D563B5EA1FE96F80A4293AE2FCC02AAF" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_15C8BB4E62DB7B200DAC3AE2FCC3C80B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_472E7BA9C0F3D4612BA33AE2FCC3922B_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_15C8BB4E62DB7B200DAC3AE2FCC3C80B" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_472E7BA9C0F3D4612BA33AE2FCC3922B_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_472E7BA9C0F3D4612BA33AE2FCC3922B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_15C8BB4E62DB7B200DAC3AE2FCC3C80B" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_472E7BA9C0F3D4612BA33AE2FCC3922B" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember" xlink:label="loc_hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember_C20E343A7C693D5B206F3AE2FCC3ADE9" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_472E7BA9C0F3D4612BA33AE2FCC3922B" xlink:to="loc_hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember_C20E343A7C693D5B206F3AE2FCC3ADE9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_B506D991066B33D62BCE3AE2FCC45FA2" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1869B62D08D6C1C2FC203AE2FCC4F141" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_B506D991066B33D62BCE3AE2FCC45FA2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold_036D8C573097FF16C9E83AE2FCC43A21" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1869B62D08D6C1C2FC203AE2FCC4F141" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold_036D8C573097FF16C9E83AE2FCC43A21" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax" xlink:label="loc_us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax_9E0DFEEA4DC50098F76D3AE2FCC40E5D" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1869B62D08D6C1C2FC203AE2FCC4F141" xlink:to="loc_us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax_9E0DFEEA4DC50098F76D3AE2FCC40E5D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_2D2169F866FCFD0FB0C13AE2FCC4370A" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1869B62D08D6C1C2FC203AE2FCC4F141" xlink:to="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_2D2169F866FCFD0FB0C13AE2FCC4370A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense_C0BC5D61D9B4CB1D5D273AE2FCC5D9B2" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1869B62D08D6C1C2FC203AE2FCC4F141" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense_C0BC5D61D9B4CB1D5D273AE2FCC5D9B2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense_82BD3A5F5D268ECF73393AE2FCC50C97" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1869B62D08D6C1C2FC203AE2FCC4F141" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense_82BD3A5F5D268ECF73393AE2FCC50C97" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_059634C3A0722E6D2C3A3AE2FCC53578" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1869B62D08D6C1C2FC203AE2FCC4F141" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_059634C3A0722E6D2C3A3AE2FCC53578" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet" xlink:label="loc_us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet_D1D2CFAF223905A79C0A3AE2FCC55E5D" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1869B62D08D6C1C2FC203AE2FCC4F141" xlink:to="loc_us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet_D1D2CFAF223905A79C0A3AE2FCC55E5D" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/AcquisitionsAndDispositionsTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/CapitalStock" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/CapitalStockDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfWarrantOrRightLineItems" xlink:label="loc_us-gaap_ClassOfWarrantOrRightLineItems_99B3E85B5DC28201C9AC5F8AE8FEF173" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfWarrantOrRightTable" xlink:label="loc_us-gaap_ClassOfWarrantOrRightTable_9FCE3690C40F7217AA0D5F8AE8FD27EE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_99B3E85B5DC28201C9AC5F8AE8FEF173" xlink:to="loc_us-gaap_ClassOfWarrantOrRightTable_9FCE3690C40F7217AA0D5F8AE8FD27EE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_A5E617FDE5B7F0B5C1215F8AE8FE2EC0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfWarrantOrRightTable_9FCE3690C40F7217AA0D5F8AE8FD27EE" xlink:to="loc_us-gaap_StatementClassOfStockAxis_A5E617FDE5B7F0B5C1215F8AE8FE2EC0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_58D1B510475F038A603B5F8AE8FEBB4A_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_A5E617FDE5B7F0B5C1215F8AE8FE2EC0" xlink:to="loc_us-gaap_ClassOfStockDomain_58D1B510475F038A603B5F8AE8FEBB4A_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_58D1B510475F038A603B5F8AE8FEBB4A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_A5E617FDE5B7F0B5C1215F8AE8FE2EC0" xlink:to="loc_us-gaap_ClassOfStockDomain_58D1B510475F038A603B5F8AE8FEBB4A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TreasuryStockMember" xlink:label="loc_us-gaap_TreasuryStockMember_4A6B2202A0A94F47D2545F8AE8FEA43C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_58D1B510475F038A603B5F8AE8FEBB4A" xlink:to="loc_us-gaap_TreasuryStockMember_4A6B2202A0A94F47D2545F8AE8FEA43C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_B7A20C8CC8459DAC9F115F8AE8FFD01D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_99B3E85B5DC28201C9AC5F8AE8FEF173" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_B7A20C8CC8459DAC9F115F8AE8FFD01D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_B2E083858B52482E3AA85F8AE8FF6C62" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_99B3E85B5DC28201C9AC5F8AE8FEF173" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_B2E083858B52482E3AA85F8AE8FF6C62" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_A373B1309B4D9CEB373E5F8AE8FFD572" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_99B3E85B5DC28201C9AC5F8AE8FEF173" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_A373B1309B4D9CEB373E5F8AE8FFD572" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_14210CC64A7B388FC9FD5F8AE8FF5BCC" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_99B3E85B5DC28201C9AC5F8AE8FEF173" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_14210CC64A7B388FC9FD5F8AE8FF5BCC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaap_PreferredStockSharesIssued_A7AD31A209EA9C943D425F8AE8FF2E97" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_99B3E85B5DC28201C9AC5F8AE8FEF173" xlink:to="loc_us-gaap_PreferredStockSharesIssued_A7AD31A209EA9C943D425F8AE8FF2E97" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/CapitalStockDetails2" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaap_ClassOfStockLineItems_D32CA137E6089F3F9A3A5F8AE8EE46DF" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_D58C7AED4F32A1C584075F8AE8EE2ABE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_D32CA137E6089F3F9A3A5F8AE8EE46DF" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_D58C7AED4F32A1C584075F8AE8EE2ABE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_1A3DDC20F6BCE4D974E95F8AE8EED352" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_D58C7AED4F32A1C584075F8AE8EE2ABE" xlink:to="loc_us-gaap_StatementClassOfStockAxis_1A3DDC20F6BCE4D974E95F8AE8EED352" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_5181C740CB20181A1CC05F8AE8EEFDA1_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_1A3DDC20F6BCE4D974E95F8AE8EED352" xlink:to="loc_us-gaap_ClassOfStockDomain_5181C740CB20181A1CC05F8AE8EEFDA1_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_5181C740CB20181A1CC05F8AE8EEFDA1" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_1A3DDC20F6BCE4D974E95F8AE8EED352" xlink:to="loc_us-gaap_ClassOfStockDomain_5181C740CB20181A1CC05F8AE8EEFDA1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TreasuryStockMember" xlink:label="loc_us-gaap_TreasuryStockMember_4EEC8196F220915A716B5F8AE8EEF700" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_5181C740CB20181A1CC05F8AE8EEFDA1" xlink:to="loc_us-gaap_TreasuryStockMember_4EEC8196F220915A716B5F8AE8EEF700" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CommonStockSharesOutstandingMember" xlink:label="loc_hsc_CommonStockSharesOutstandingMember_E6D88607EE79629240945F8AE8EEB0EB" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_5181C740CB20181A1CC05F8AE8EEFDA1" xlink:to="loc_hsc_CommonStockSharesOutstandingMember_E6D88607EE79629240945F8AE8EEB0EB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_F4DD3F86F44BD31C8E6D5F8AE8EEF3EE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_D32CA137E6089F3F9A3A5F8AE8EE46DF" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_F4DD3F86F44BD31C8E6D5F8AE8EEF3EE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued_79BF8B75F62180BB21B85F8AE8EE3BD4" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_F4DD3F86F44BD31C8E6D5F8AE8EEF3EE" xlink:to="loc_us-gaap_CommonStockSharesIssued_79BF8B75F62180BB21B85F8AE8EE3BD4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TreasuryStockShares" xlink:label="loc_us-gaap_TreasuryStockShares_37E55DCAD38810B162765F8AE8F2FEDC" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_F4DD3F86F44BD31C8E6D5F8AE8EEF3EE" xlink:to="loc_us-gaap_TreasuryStockShares_37E55DCAD38810B162765F8AE8F2FEDC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_445688065984A75CDCE95F8AE8F2E599" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_F4DD3F86F44BD31C8E6D5F8AE8EEF3EE" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_445688065984A75CDCE95F8AE8F2E599" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_B7C2005E8B132AAC90F95F8AE8F25D7C" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_F4DD3F86F44BD31C8E6D5F8AE8EEF3EE" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_B7C2005E8B132AAC90F95F8AE8F25D7C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesOther" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesOther_1568CD2143A3E0FCDAE15F8AE8F2D1FF" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_F4DD3F86F44BD31C8E6D5F8AE8EEF3EE" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesOther_1568CD2143A3E0FCDAE15F8AE8F2D1FF" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_StockIssuedDuringPeriodStockAppreciationRights" xlink:label="loc_hsc_StockIssuedDuringPeriodStockAppreciationRights_60A93B9D1B1722A5BEC25F8AE8F2A855" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_F4DD3F86F44BD31C8E6D5F8AE8EEF3EE" xlink:to="loc_hsc_StockIssuedDuringPeriodStockAppreciationRights_60A93B9D1B1722A5BEC25F8AE8F2A855" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TreasuryStockSharesAcquired" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_3A2E0A3DD54E473083185F8AE8F23D06" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_F4DD3F86F44BD31C8E6D5F8AE8EEF3EE" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_3A2E0A3DD54E473083185F8AE8F23D06" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/CapitalStockDetails3" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_B438133064A9168AF7D13AE2F8B7E938" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_45246C0AA95ADFDD80D63AE2F8B514DA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_B438133064A9168AF7D13AE2F8B7E938" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_45246C0AA95ADFDD80D63AE2F8B514DA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_04F286BD850A25E55A4D3AE2F8B5B3F8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_45246C0AA95ADFDD80D63AE2F8B514DA" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_04F286BD850A25E55A4D3AE2F8B5B3F8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_BDA62F43D8F178483A113AE2F8B6062D_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_04F286BD850A25E55A4D3AE2F8B5B3F8" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_BDA62F43D8F178483A113AE2F8B6062D_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_BDA62F43D8F178483A113AE2F8B6062D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_04F286BD850A25E55A4D3AE2F8B5B3F8" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_BDA62F43D8F178483A113AE2F8B6062D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_B85EBECBD74E098863B93AE2F8B6BA79" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_BDA62F43D8F178483A113AE2F8B6062D" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_B85EBECBD74E098863B93AE2F8B6BA79" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_928848D0EB59D083C3193AE2F8B6BAFA" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_BDA62F43D8F178483A113AE2F8B6062D" xlink:to="loc_us-gaap_EmployeeStockOptionMember_928848D0EB59D083C3193AE2F8B6BAFA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockAppreciationRightsSARSMember" xlink:label="loc_us-gaap_StockAppreciationRightsSARSMember_E857E369381AC61412783AE2F8B62352" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_BDA62F43D8F178483A113AE2F8B6062D" xlink:to="loc_us-gaap_StockAppreciationRightsSARSMember_E857E369381AC61412783AE2F8B62352" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="loc_us-gaap_PerformanceSharesMember_835C72BF6B89CF87F4F33AE2F8B649FE" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_BDA62F43D8F178483A113AE2F8B6062D" xlink:to="loc_us-gaap_PerformanceSharesMember_835C72BF6B89CF87F4F33AE2F8B649FE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_661BABC50F381AAA00253AE2F8B7131B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_B438133064A9168AF7D13AE2F8B7E938" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_661BABC50F381AAA00253AE2F8B7131B" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/CapitalStockTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/CommitmentsAndContingencies" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/CommitmentsAndContingenciesDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingenciesLineItems" xlink:label="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingenciesTable" xlink:label="loc_us-gaap_LossContingenciesTable_2543053FAAEA35969BF854C577665BB8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_us-gaap_LossContingenciesTable_2543053FAAEA35969BF854C577665BB8" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MajorCustomersAxis" xlink:label="loc_srt_MajorCustomersAxis_F47F0899817F3276F09954C57766454C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_2543053FAAEA35969BF854C577665BB8" xlink:to="loc_srt_MajorCustomersAxis_F47F0899817F3276F09954C57766454C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_261E9D61E0F81EED875F54C577669263_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_F47F0899817F3276F09954C57766454C" xlink:to="loc_srt_NameOfMajorCustomerDomain_261E9D61E0F81EED875F54C577669263_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_261E9D61E0F81EED875F54C577669263" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_F47F0899817F3276F09954C57766454C" xlink:to="loc_srt_NameOfMajorCustomerDomain_261E9D61E0F81EED875F54C577669263" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CSNMember" xlink:label="loc_hsc_CSNMember_160A8A89BFD4C947487A54C577665FD7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_261E9D61E0F81EED875F54C577669263" xlink:to="loc_hsc_CSNMember_160A8A89BFD4C947487A54C577665FD7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_9BADDE50B07ADA62BA2554C5776687F7" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_2543053FAAEA35969BF854C577665BB8" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_9BADDE50B07ADA62BA2554C5776687F7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_7AD368735DFB4E1E6C6C54C577661E18_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_9BADDE50B07ADA62BA2554C5776687F7" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_7AD368735DFB4E1E6C6C54C577661E18_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_7AD368735DFB4E1E6C6C54C577661E18" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_9BADDE50B07ADA62BA2554C5776687F7" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_7AD368735DFB4E1E6C6C54C577661E18" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SubsidiaryConcentrationRiskMember" xlink:label="loc_hsc_SubsidiaryConcentrationRiskMember_B234B93877E8227C275D54C577661588" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_7AD368735DFB4E1E6C6C54C577661E18" xlink:to="loc_hsc_SubsidiaryConcentrationRiskMember_B234B93877E8227C275D54C577661588" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ConsolidatedRevenueNetMember" xlink:label="loc_hsc_ConsolidatedRevenueNetMember_C144F5B145A8DCBFBFED54C57766B9A5" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_7AD368735DFB4E1E6C6C54C577661E18" xlink:to="loc_hsc_ConsolidatedRevenueNetMember_C144F5B145A8DCBFBFED54C57766B9A5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_E65D68A7EE080E1B6F3154C577661518" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_2543053FAAEA35969BF854C577665BB8" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_E65D68A7EE080E1B6F3154C577661518" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_C97E1284064E72F0722354C57766982F_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_E65D68A7EE080E1B6F3154C577661518" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_C97E1284064E72F0722354C57766982F_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_C97E1284064E72F0722354C57766982F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_E65D68A7EE080E1B6F3154C577661518" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_C97E1284064E72F0722354C57766982F" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SubsidiaryConcentrationRiskMember" xlink:label="loc_hsc_SubsidiaryConcentrationRiskMember_42E9DECDB839D6C4255854C577666947" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_C97E1284064E72F0722354C57766982F" xlink:to="loc_hsc_SubsidiaryConcentrationRiskMember_42E9DECDB839D6C4255854C577666947" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_LitigationCaseAxis" xlink:label="loc_srt_LitigationCaseAxis_23A678DCBF0A29E1D99154C57766F443" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_2543053FAAEA35969BF854C577665BB8" xlink:to="loc_srt_LitigationCaseAxis_23A678DCBF0A29E1D99154C57766F443" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_LitigationCaseTypeDomain" xlink:label="loc_srt_LitigationCaseTypeDomain_09A2EA417BEFC008430254C577669769_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_23A678DCBF0A29E1D99154C57766F443" xlink:to="loc_srt_LitigationCaseTypeDomain_09A2EA417BEFC008430254C577669769_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_LitigationCaseTypeDomain" xlink:label="loc_srt_LitigationCaseTypeDomain_09A2EA417BEFC008430254C577669769" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_23A678DCBF0A29E1D99154C57766F443" xlink:to="loc_srt_LitigationCaseTypeDomain_09A2EA417BEFC008430254C577669769" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_PennsylvaniaDepartmentOfEnvironmentalProtectionProcessedSlagMember" xlink:label="loc_hsc_PennsylvaniaDepartmentOfEnvironmentalProtectionProcessedSlagMember_1E773033B5FD8C57796954C577666772" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_09A2EA417BEFC008430254C577669769" xlink:to="loc_hsc_PennsylvaniaDepartmentOfEnvironmentalProtectionProcessedSlagMember_1E773033B5FD8C57796954C577666772" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatutoryAccountingPracticesByJurisdictionAxis" xlink:label="loc_us-gaap_StatutoryAccountingPracticesByJurisdictionAxis_1B08505A5A801B9ABAD854C5776619FA" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_2543053FAAEA35969BF854C577665BB8" xlink:to="loc_us-gaap_StatutoryAccountingPracticesByJurisdictionAxis_1B08505A5A801B9ABAD854C5776619FA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatutoryAccountingPracticesJurisdictionDomain" xlink:label="loc_us-gaap_StatutoryAccountingPracticesJurisdictionDomain_115F534C58235777947A54C57766B0DB_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatutoryAccountingPracticesByJurisdictionAxis_1B08505A5A801B9ABAD854C5776619FA" xlink:to="loc_us-gaap_StatutoryAccountingPracticesJurisdictionDomain_115F534C58235777947A54C57766B0DB_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatutoryAccountingPracticesJurisdictionDomain" xlink:label="loc_us-gaap_StatutoryAccountingPracticesJurisdictionDomain_115F534C58235777947A54C57766B0DB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatutoryAccountingPracticesByJurisdictionAxis_1B08505A5A801B9ABAD854C5776619FA" xlink:to="loc_us-gaap_StatutoryAccountingPracticesJurisdictionDomain_115F534C58235777947A54C57766B0DB" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SaoPauloStateRevenueAuthorityMember" xlink:label="loc_hsc_SaoPauloStateRevenueAuthorityMember_8CEE8B6CA3C0562596BF54C577769C92" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatutoryAccountingPracticesJurisdictionDomain_115F534C58235777947A54C57766B0DB" xlink:to="loc_hsc_SaoPauloStateRevenueAuthorityMember_8CEE8B6CA3C0562596BF54C577769C92" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_NewYorkCountyAsManagedByNewYorkSupremeCourtMember" xlink:label="loc_hsc_NewYorkCountyAsManagedByNewYorkSupremeCourtMember_C9C5E30B65EE3D6FC7EA54C577768829" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatutoryAccountingPracticesJurisdictionDomain_115F534C58235777947A54C57766B0DB" xlink:to="loc_hsc_NewYorkCountyAsManagedByNewYorkSupremeCourtMember_C9C5E30B65EE3D6FC7EA54C577768829" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_NewYorkStateSupremeCourtCountiesExcludingNewYorkCountyMember" xlink:label="loc_hsc_NewYorkStateSupremeCourtCountiesExcludingNewYorkCountyMember_7E01844EBA87096E1D2954C57776CFF5" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatutoryAccountingPracticesJurisdictionDomain_115F534C58235777947A54C57766B0DB" xlink:to="loc_hsc_NewYorkStateSupremeCourtCountiesExcludingNewYorkCountyMember_7E01844EBA87096E1D2954C57776CFF5" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CourtsLocatedInStatesOtherThanNewYorkMember" xlink:label="loc_hsc_CourtsLocatedInStatesOtherThanNewYorkMember_191360795D3594B9097754C577763377" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatutoryAccountingPracticesJurisdictionDomain_115F534C58235777947A54C57766B0DB" xlink:to="loc_hsc_CourtsLocatedInStatesOtherThanNewYorkMember_191360795D3594B9097754C577763377" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_NL" xlink:label="loc_country_NL_E9EB6853B010AEA115DB54C5777633D7" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatutoryAccountingPracticesJurisdictionDomain_115F534C58235777947A54C57766B0DB" xlink:to="loc_country_NL_E9EB6853B010AEA115DB54C5777633D7" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AlleghenyCountyHealthDepartmentMember" xlink:label="loc_hsc_AlleghenyCountyHealthDepartmentMember_5ED71EF38B00917E2A3D54C57776B329" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatutoryAccountingPracticesJurisdictionDomain_115F534C58235777947A54C57766B0DB" xlink:to="loc_hsc_AlleghenyCountyHealthDepartmentMember_5ED71EF38B00917E2A3D54C57776B329" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LitigationStatusAxis" xlink:label="loc_us-gaap_LitigationStatusAxis_56DEBF32FC0A2E44605A54C57776490F" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_2543053FAAEA35969BF854C577665BB8" xlink:to="loc_us-gaap_LitigationStatusAxis_56DEBF32FC0A2E44605A54C57776490F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LitigationStatusDomain" xlink:label="loc_us-gaap_LitigationStatusDomain_0925E5C7D2D3DDD0C71E54C577762AD5_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LitigationStatusAxis_56DEBF32FC0A2E44605A54C57776490F" xlink:to="loc_us-gaap_LitigationStatusDomain_0925E5C7D2D3DDD0C71E54C577762AD5_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LitigationStatusDomain" xlink:label="loc_us-gaap_LitigationStatusDomain_0925E5C7D2D3DDD0C71E54C577762AD5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LitigationStatusAxis_56DEBF32FC0A2E44605A54C57776490F" xlink:to="loc_us-gaap_LitigationStatusDomain_0925E5C7D2D3DDD0C71E54C577762AD5" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_PendingAndFutureLitigationDeferredOrInactiveDocketMember" xlink:label="loc_hsc_PendingAndFutureLitigationDeferredOrInactiveDocketMember_9E1FB005557718A7FE9554C57776A0BB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LitigationStatusDomain_0925E5C7D2D3DDD0C71E54C577762AD5" xlink:to="loc_hsc_PendingAndFutureLitigationDeferredOrInactiveDocketMember_9E1FB005557718A7FE9554C57776A0BB" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_PendingLitigationActiveOrInExtremisDocketMember" xlink:label="loc_hsc_PendingLitigationActiveOrInExtremisDocketMember_47613C22117529AAEE9C54C57776421F" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LitigationStatusDomain_0925E5C7D2D3DDD0C71E54C577762AD5" xlink:to="loc_hsc_PendingLitigationActiveOrInExtremisDocketMember_47613C22117529AAEE9C54C57776421F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_605806A56E8FFA62E6B254C57776D819" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_2543053FAAEA35969BF854C577665BB8" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_605806A56E8FFA62E6B254C57776D819" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="loc_us-gaap_LossContingencyNatureDomain_A8936DFFDB55A76D6B1154C5777673FC_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_605806A56E8FFA62E6B254C57776D819" xlink:to="loc_us-gaap_LossContingencyNatureDomain_A8936DFFDB55A76D6B1154C5777673FC_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="loc_us-gaap_LossContingencyNatureDomain_A8936DFFDB55A76D6B1154C5777673FC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_605806A56E8FFA62E6B254C57776D819" xlink:to="loc_us-gaap_LossContingencyNatureDomain_A8936DFFDB55A76D6B1154C5777673FC" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ValueAddedTaxAssessmentsJanuary2004ToMay2005Member" xlink:label="loc_hsc_ValueAddedTaxAssessmentsJanuary2004ToMay2005Member_F9A3C1AC499467CFF32654C577760C35" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_A8936DFFDB55A76D6B1154C5777673FC" xlink:to="loc_hsc_ValueAddedTaxAssessmentsJanuary2004ToMay2005Member_F9A3C1AC499467CFF32654C577760C35" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ValueAddedTaxAssessmentsJanuary2002ToDecember2003Member" xlink:label="loc_hsc_ValueAddedTaxAssessmentsJanuary2002ToDecember2003Member_221EF070379F09528DAE54C57776A8BC" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_A8936DFFDB55A76D6B1154C5777673FC" xlink:to="loc_hsc_ValueAddedTaxAssessmentsJanuary2002ToDecember2003Member_221EF070379F09528DAE54C57776A8BC" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_LosscontingencyBrazilianlaborclaimsMember" xlink:label="loc_hsc_LosscontingencyBrazilianlaborclaimsMember_AD4940E2A7A2AF767D0854C577765CC1" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_A8936DFFDB55A76D6B1154C5777673FC" xlink:to="loc_hsc_LosscontingencyBrazilianlaborclaimsMember_AD4940E2A7A2AF767D0854C577765CC1" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_OtherIncludingAsbestosRelatedClaimsMember" xlink:label="loc_hsc_OtherIncludingAsbestosRelatedClaimsMember_1721C7404F5409E6B9D854C57776B3EE" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_A8936DFFDB55A76D6B1154C5777673FC" xlink:to="loc_hsc_OtherIncludingAsbestosRelatedClaimsMember_1721C7404F5409E6B9D854C57776B3EE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_2ADA197A1D65E246766554C57776110E" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_2543053FAAEA35969BF854C577665BB8" xlink:to="loc_srt_RangeAxis_2ADA197A1D65E246766554C57776110E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_F1B6E9D1F3ACF77B9A7B54C577764609_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_2ADA197A1D65E246766554C57776110E" xlink:to="loc_srt_RangeMember_F1B6E9D1F3ACF77B9A7B54C577764609_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_F1B6E9D1F3ACF77B9A7B54C577764609" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_2ADA197A1D65E246766554C57776110E" xlink:to="loc_srt_RangeMember_F1B6E9D1F3ACF77B9A7B54C577764609" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_109872F054831FA26A0954C577761EBB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_F1B6E9D1F3ACF77B9A7B54C577764609" xlink:to="loc_srt_MinimumMember_109872F054831FA26A0954C577761EBB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_23AF5CE42B360A65464454C57776796E" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_F1B6E9D1F3ACF77B9A7B54C577764609" xlink:to="loc_srt_MaximumMember_23AF5CE42B360A65464454C57776796E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_LossContingencyDamagesSoughtPrincipalAmount" xlink:label="loc_hsc_LossContingencyDamagesSoughtPrincipalAmount_7DFEB618B89EDBBE020B54C57776D212" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_hsc_LossContingencyDamagesSoughtPrincipalAmount_7DFEB618B89EDBBE020B54C57776D212" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_LossContingencyDamagesSoughtInterestPenaltiesAndFees" xlink:label="loc_hsc_LossContingencyDamagesSoughtInterestPenaltiesAndFees_F148754BC4F90BB51E3B54C5777621FC" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_hsc_LossContingencyDamagesSoughtInterestPenaltiesAndFees_F148754BC4F90BB51E3B54C5777621FC" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_LossContingencyReducedPenalty" xlink:label="loc_hsc_LossContingencyReducedPenalty_39B778008418D61DD83C54C57776BDAA" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_hsc_LossContingencyReducedPenalty_39B778008418D61DD83C54C57776BDAA" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_LossContingencyReducedPenaltyIncludingInterest" xlink:label="loc_hsc_LossContingencyReducedPenaltyIncludingInterest_3B075857D04538CC12F054C5777644D5" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_hsc_LossContingencyReducedPenaltyIncludingInterest_3B075857D04538CC12F054C5777644D5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyPendingClaimsNumber" xlink:label="loc_us-gaap_LossContingencyPendingClaimsNumber_D6B36D37BD5243ABCC2654C577764F00" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_us-gaap_LossContingencyPendingClaimsNumber_D6B36D37BD5243ABCC2654C577764F00" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyDamagesSoughtValue" xlink:label="loc_us-gaap_LossContingencyDamagesSoughtValue_0565DC964870639708A754C5777615E9" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_us-gaap_LossContingencyDamagesSoughtValue_0565DC964870639708A754C5777615E9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyAccrualProvision" xlink:label="loc_us-gaap_LossContingencyAccrualProvision_9EE00677A3C1C7D05F3654C57776EDBA" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_us-gaap_LossContingencyAccrualProvision_9EE00677A3C1C7D05F3654C57776EDBA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyAccrualAtCarryingValue" xlink:label="loc_us-gaap_LossContingencyAccrualAtCarryingValue_5BA568F34B366047E19354C57776EB0A" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_us-gaap_LossContingencyAccrualAtCarryingValue_5BA568F34B366047E19354C57776EB0A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LitigationSettlementAmountAwardedToOtherParty" xlink:label="loc_us-gaap_LitigationSettlementAmountAwardedToOtherParty_5FB5471EFF916E1F365B54C577762BED" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_us-gaap_LitigationSettlementAmountAwardedToOtherParty_5FB5471EFF916E1F365B54C577762BED" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_C93E63CE7E8758F5E0C054C577769BF8" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_C93E63CE7E8758F5E0C054C577769BF8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccrualForEnvironmentalLossContingencies" xlink:label="loc_us-gaap_AccrualForEnvironmentalLossContingencies_008A13CA0E27CC9F706554C577765787" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_us-gaap_AccrualForEnvironmentalLossContingencies_008A13CA0E27CC9F706554C577765787" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_Penaltiesperday" xlink:label="loc_hsc_Penaltiesperday_D3E0724E8AE5204239C554C57776D99D" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_hsc_Penaltiesperday_D3E0724E8AE5204239C554C57776D99D" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_Penalties" xlink:label="loc_hsc_Penalties_6CAB135D702646050EB154C57776EFA1" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_hsc_Penalties_6CAB135D702646050EB154C57776EFA1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyNumberOfDefendants" xlink:label="loc_us-gaap_LossContingencyNumberOfDefendants_A91119FA95C73ED15B1C54C577768E91" xlink:type="locator"/>
<link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_us-gaap_LossContingencyNumberOfDefendants_A91119FA95C73ED15B1C54C577768E91" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyClaimsDismissedNumber" xlink:label="loc_us-gaap_LossContingencyClaimsDismissedNumber_4F20A0DDD2F7E231D29E54C57776933A" xlink:type="locator"/>
<link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_us-gaap_LossContingencyClaimsDismissedNumber_4F20A0DDD2F7E231D29E54C57776933A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_3FB38DDB4542358F5E2F54C57776150C" xlink:type="locator"/>
<link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_CFCA715CDB0E3A4FAC6654C57776BE54" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_3FB38DDB4542358F5E2F54C57776150C" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/ComponentsOfAccumulatedOtherComprehensiveLoss" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/ComponentsOfAccumulatedOtherComprehensiveLossDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_C44BA4E02F0AD998338954C573AD7BE7" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_FC19BF13F2EBC89857F454C573AD7F01" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_C44BA4E02F0AD998338954C573AD7BE7" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_FC19BF13F2EBC89857F454C573AD7F01" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_63E863E5563D882D522954C573AD6570" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_FC19BF13F2EBC89857F454C573AD7F01" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_63E863E5563D882D522954C573AD6570" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_005E000CEEAC43368C2254C573AD1A3C_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_63E863E5563D882D522954C573AD6570" xlink:to="loc_us-gaap_TypeOfAdoptionMember_005E000CEEAC43368C2254C573AD1A3C_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_005E000CEEAC43368C2254C573AD1A3C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_63E863E5563D882D522954C573AD6570" xlink:to="loc_us-gaap_TypeOfAdoptionMember_005E000CEEAC43368C2254C573AD1A3C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingStandardsUpdate201409Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201409Member_43CDD66A3012161B568E54C573AD2BE5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_005E000CEEAC43368C2254C573AD1A3C" xlink:to="loc_us-gaap_AccountingStandardsUpdate201409Member_43CDD66A3012161B568E54C573AD2BE5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_068F285897DD38CDA9AF54C573AD889F" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_FC19BF13F2EBC89857F454C573AD7F01" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_068F285897DD38CDA9AF54C573AD889F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_04DE959258C5BC86EBC154C573ADB24A_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_068F285897DD38CDA9AF54C573AD889F" xlink:to="loc_us-gaap_EquityComponentDomain_04DE959258C5BC86EBC154C573ADB24A_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_04DE959258C5BC86EBC154C573ADB24A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_068F285897DD38CDA9AF54C573AD889F" xlink:to="loc_us-gaap_EquityComponentDomain_04DE959258C5BC86EBC154C573ADB24A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_ADF876BA301B09B5CE1954C573ADC02B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_04DE959258C5BC86EBC154C573ADB24A" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_ADF876BA301B09B5CE1954C573ADC02B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_69DB17D7E5B24D8DFA2354C573AD2AC4" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_04DE959258C5BC86EBC154C573ADB24A" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_69DB17D7E5B24D8DFA2354C573AD2AC4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_060F7BDA543B4D51C13654C573ADF817" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_04DE959258C5BC86EBC154C573ADB24A" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_060F7BDA543B4D51C13654C573ADF817" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_40402F2E7AF50DC866E454C573AD0BC6" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_04DE959258C5BC86EBC154C573ADB24A" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_40402F2E7AF50DC866E454C573AD0BC6" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_30F0E99EA802B1699A5154C573AD9B23" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_04DE959258C5BC86EBC154C573ADB24A" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_30F0E99EA802B1699A5154C573AD9B23" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_3B3200BE8D18AB748C5A54C573AD2198" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_C44BA4E02F0AD998338954C573AD7BE7" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_3B3200BE8D18AB748C5A54C573AD2198" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_2C9F1B1707ACF264911254C573AD0E6A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_3B3200BE8D18AB748C5A54C573AD2198" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_2C9F1B1707ACF264911254C573AD0E6A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_51A0A37E6AA84D5989A154C573AD60D1" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_3B3200BE8D18AB748C5A54C573AD2198" xlink:to="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_51A0A37E6AA84D5989A154C573AD60D1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_1A337ACB8C7D6885947F54C573AD81D4" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_3B3200BE8D18AB748C5A54C573AD2198" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_1A337ACB8C7D6885947F54C573AD81D4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_CC313F7FB81FA754668C54C573AD9339" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_3B3200BE8D18AB748C5A54C573AD2198" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_CC313F7FB81FA754668C54C573AD9339" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_9F27B09363546710490654C573ADC008" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_3B3200BE8D18AB748C5A54C573AD2198" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_9F27B09363546710490654C573ADC008" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest_230C66A29F9E049AFAA754C573AD86F5" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_3B3200BE8D18AB748C5A54C573AD2198" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest_230C66A29F9E049AFAA754C573AD86F5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_6B5B77E41949DFBA662854C573BCDC6C" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_3B3200BE8D18AB748C5A54C573AD2198" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_6B5B77E41949DFBA662854C573BCDC6C" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/ComponentsOfAccumulatedOtherComprehensiveLossDetails2" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems" xlink:label="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_B0D341B15CB220D1693C3B107575D74F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_B0D341B15CB220D1693C3B107575D74F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_811EE756D5EB08280D093B1075754590" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_B0D341B15CB220D1693C3B107575D74F" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_811EE756D5EB08280D093B1075754590" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_11B4AD84EA29BD441FCB3B10757650B3_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_811EE756D5EB08280D093B1075754590" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_11B4AD84EA29BD441FCB3B10757650B3_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_11B4AD84EA29BD441FCB3B10757650B3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_811EE756D5EB08280D093B1075754590" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_11B4AD84EA29BD441FCB3B10757650B3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_A0BF7AD71CCAAE8F104C3B1075769BBF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_11B4AD84EA29BD441FCB3B10757650B3" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_A0BF7AD71CCAAE8F104C3B1075769BBF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_3CB9B9DBC13B1A0794CE3B1075760177" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_B0D341B15CB220D1693C3B107575D74F" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_3CB9B9DBC13B1A0794CE3B1075760177" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_A80FE832F280810F65553B1075773649_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3CB9B9DBC13B1A0794CE3B1075760177" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_A80FE832F280810F65553B1075773649_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_A80FE832F280810F65553B1075773649" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3CB9B9DBC13B1A0794CE3B1075760177" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_A80FE832F280810F65553B1075773649" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignExchangeForwardMember" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_0458E9736A6E777372E93B10757C9003" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_A80FE832F280810F65553B1075773649" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_0458E9736A6E777372E93B10757C9003" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CrossCurrencyInterestRateContractMember" xlink:label="loc_us-gaap_CrossCurrencyInterestRateContractMember_81B072676D06648AE3733B10757C6DC0" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_A80FE832F280810F65553B1075773649" xlink:to="loc_us-gaap_CrossCurrencyInterestRateContractMember_81B072676D06648AE3733B10757C6DC0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="loc_us-gaap_InterestRateSwapMember_EFB4AB3277922D8EE3FF3B10757CF02B" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_A80FE832F280810F65553B1075773649" xlink:to="loc_us-gaap_InterestRateSwapMember_EFB4AB3277922D8EE3FF3B10757CF02B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_AA789C84501BA26D06C63B10757D2D5E" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_B0D341B15CB220D1693C3B107575D74F" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_AA789C84501BA26D06C63B10757D2D5E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_F049C97A5226B94BCF233B10757D3CE3_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_AA789C84501BA26D06C63B10757D2D5E" xlink:to="loc_us-gaap_EquityComponentDomain_F049C97A5226B94BCF233B10757D3CE3_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_F049C97A5226B94BCF233B10757D3CE3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_AA789C84501BA26D06C63B10757D2D5E" xlink:to="loc_us-gaap_EquityComponentDomain_F049C97A5226B94BCF233B10757D3CE3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_C15F2EC8206426EABBA33B10757DD4D3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_F049C97A5226B94BCF233B10757D3CE3" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_C15F2EC8206426EABBA33B10757DD4D3" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanActuarialGainLossMember" xlink:label="loc_hsc_DefinedBenefitPlanActuarialGainLossMember_EAEE2790CF31BAC80A093B10757D8CC4" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_C15F2EC8206426EABBA33B10757DD4D3" xlink:to="loc_hsc_DefinedBenefitPlanActuarialGainLossMember_EAEE2790CF31BAC80A093B10757D8CC4" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanPriorServiceCostsMember" xlink:label="loc_hsc_DefinedBenefitPlanPriorServiceCostsMember_1CD98DB0A2D76C0A45AF3B10757E1856" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_C15F2EC8206426EABBA33B10757DD4D3" xlink:to="loc_hsc_DefinedBenefitPlanPriorServiceCostsMember_1CD98DB0A2D76C0A45AF3B10757E1856" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SettlementCurtailmentLossesMember" xlink:label="loc_hsc_SettlementCurtailmentLossesMember_CE62124892F16E7C78843B10757EDA54" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_C15F2EC8206426EABBA33B10757DD4D3" xlink:to="loc_hsc_SettlementCurtailmentLossesMember_CE62124892F16E7C78843B10757EDA54" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_E29AAFD3AAF2B2A58D773BBBA90D09DF" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_F049C97A5226B94BCF233B10757D3CE3" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_E29AAFD3AAF2B2A58D773BBBA90D09DF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_B7F3BE1CCBD8381DAC1F3B10757E3C3E" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_F049C97A5226B94BCF233B10757D3CE3" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_B7F3BE1CCBD8381DAC1F3B10757E3C3E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_834283656D1827AD62973B10757E52AC" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_F049C97A5226B94BCF233B10757D3CE3" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_834283656D1827AD62973B10757E52AC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionAndOtherPostretirementBenefitExpense" xlink:label="loc_us-gaap_PensionAndOtherPostretirementBenefitExpense_4C72BF84CB217624D5CB3B10757F2575" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_us-gaap_PensionAndOtherPostretirementBenefitExpense_4C72BF84CB217624D5CB3B10757F2575" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_13D66DF90C24C865DD0A3B10757F3AB7" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_us-gaap_Revenues_13D66DF90C24C865DD0A3B10757F3AB7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_91BA2B54BF2FEF9BC8BA3B107580E005" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_91BA2B54BF2FEF9BC8BA3B107580E005" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_529683F2B17ADC6B85CE3B107580BD88" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_us-gaap_InterestExpense_529683F2B17ADC6B85CE3B107580BD88" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_6CDCBB62B07066756B153BBE10FA5E57" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_6CDCBB62B07066756B153BBE10FA5E57" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="loc_us-gaap_CostsAndExpenses_C8D8F91D2C889072AA353B1075807599" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_us-gaap_CostsAndExpenses_C8D8F91D2C889072AA353B1075807599" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_41B59B8DD089EFC2C7373B10758099AC" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_41B59B8DD089EFC2C7373B10758099AC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_28C7057483816E1EC28E3B10758035BA" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_28C7057483816E1EC28E3B10758035BA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_3701340FF7C8BED483C23B1075811F30" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_us-gaap_ProfitLoss_3701340FF7C8BED483C23B1075811F30" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherOperatingIncomeExpenseNet" xlink:label="loc_us-gaap_OtherOperatingIncomeExpenseNet_606050F14F328CDC7D083BB7DF92CD8B" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_us-gaap_OtherOperatingIncomeExpenseNet_606050F14F328CDC7D083BB7DF92CD8B" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DiscontinuedOperationGainFromDisposalOfDiscontinuedOperationBeforeIncomeTax" xlink:label="loc_hsc_DiscontinuedOperationGainFromDisposalOfDiscontinuedOperationBeforeIncomeTax_D79A575CEA114E6028E63BBC698644D6" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeOnDerivativesLineItems_D396673D36C880C7DDE23B10757F6349" xlink:to="loc_hsc_DiscontinuedOperationGainFromDisposalOfDiscontinuedOperationBeforeIncomeTax_D79A575CEA114E6028E63BBC698644D6" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/ComponentsOfAccumulatedOtherComprehensiveLossTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/ConsolidatedBalanceSheets" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/ConsolidatedStatementsOfChangesInEquity" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_EE9A68683ADB3B6B8359591AA81CD96C" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_F01C1059AD47BA338CAB591AA81C32DF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_EE9A68683ADB3B6B8359591AA81CD96C" xlink:to="loc_us-gaap_StatementTable_F01C1059AD47BA338CAB591AA81C32DF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_4FE4C3A05FD1CACB29D0591AA81CDC56" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_F01C1059AD47BA338CAB591AA81C32DF" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_4FE4C3A05FD1CACB29D0591AA81CDC56" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_4FB645718B197DA9C9E1591AA81CF4C5_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_4FE4C3A05FD1CACB29D0591AA81CDC56" xlink:to="loc_us-gaap_EquityComponentDomain_4FB645718B197DA9C9E1591AA81CF4C5_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_4FB645718B197DA9C9E1591AA81CF4C5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_4FE4C3A05FD1CACB29D0591AA81CDC56" xlink:to="loc_us-gaap_EquityComponentDomain_4FB645718B197DA9C9E1591AA81CF4C5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_D3975F06E3FC0C725392591AA81C2396" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_4FB645718B197DA9C9E1591AA81CF4C5" xlink:to="loc_us-gaap_CommonStockMember_D3975F06E3FC0C725392591AA81C2396" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TreasuryStockMember" xlink:label="loc_us-gaap_TreasuryStockMember_60CB8CE9773659B4BD8A591AA81C40F5" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_4FB645718B197DA9C9E1591AA81CF4C5" xlink:to="loc_us-gaap_TreasuryStockMember_60CB8CE9773659B4BD8A591AA81C40F5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_C8A8AAA13D74D84B5BF0591AA81C8357" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_4FB645718B197DA9C9E1591AA81CF4C5" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_C8A8AAA13D74D84B5BF0591AA81C8357" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_DE52B38033A9A40226EB591AA81C2919" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_4FB645718B197DA9C9E1591AA81CF4C5" xlink:to="loc_us-gaap_RetainedEarningsMember_DE52B38033A9A40226EB591AA81C2919" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_5B7B59D9E1B2AB5A4E3B591AA81C9910" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_4FB645718B197DA9C9E1591AA81CF4C5" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_5B7B59D9E1B2AB5A4E3B591AA81C9910" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_A1CABDCDD9AF07611742591AA81C5139" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_4FB645718B197DA9C9E1591AA81CF4C5" xlink:to="loc_us-gaap_NoncontrollingInterestMember_A1CABDCDD9AF07611742591AA81C5139" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_EE9A68683ADB3B6B8359591AA81CD96C" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_D6D4668AA22AFF1E0238591AA81CEDAF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_D6D4668AA22AFF1E0238591AA81CEDAF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_C2EAAE511EFF211D6C17591AA81C19B7" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_C2EAAE511EFF211D6C17591AA81C19B7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_A322526AE62077E2A1C5591AA81CBFD0" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_ProfitLoss_A322526AE62077E2A1C5591AA81CBFD0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DividendsCommonStockAbstract" xlink:label="loc_us-gaap_DividendsCommonStockAbstract_B756F3AB3E0CB354E442591AA81C4C74" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_DividendsCommonStockAbstract_B756F3AB3E0CB354E442591AA81C4C74" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_A4B8795AC085650DE9D1591AA81CC670" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsCommonStockAbstract_B756F3AB3E0CB354E442591AA81C4C74" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_A4B8795AC085650DE9D1591AA81CC670" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_0FFCAB9110D8AF074134591AA81C14B0" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_0FFCAB9110D8AF074134591AA81C14B0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterestDecreaseFromRedemptions" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromRedemptions_0A27440E79838A0CB2F5591AA81CD2F5" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromRedemptions_0A27440E79838A0CB2F5591AA81CD2F5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest" xlink:label="loc_us-gaap_NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest_13E2758C89CFB385B31A591AA81CDE3D" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest_13E2758C89CFB385B31A591AA81CDE3D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NoncontrollingInterestDecreaseFromDeconsolidation" xlink:label="loc_us-gaap_NoncontrollingInterestDecreaseFromDeconsolidation_DBE0EF276126D5C20D73591AA81CB469" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_NoncontrollingInterestDecreaseFromDeconsolidation_DBE0EF276126D5C20D73591AA81CB469" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueOther" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueOther_D57B5AE4BF5EE06D63EF591AA81CE0AA" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueOther_D57B5AE4BF5EE06D63EF591AA81CE0AA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_6EA3BBE035FBC4F43D9D591AA81CEC26" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_6EA3BBE035FBC4F43D9D591AA81CEC26" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_VestingofPerformanceShareUnits" xlink:label="loc_hsc_VestingofPerformanceShareUnits_C4DABACB36453BCB5AA4591AA81CEEBD" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_hsc_VestingofPerformanceShareUnits_C4DABACB36453BCB5AA4591AA81CEEBD" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_612F26D877F24009876A591AA81C264B" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_612F26D877F24009876A591AA81C264B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_D209D469866EF4F1B7FF591AA81C6511" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6313293B79A088396167591AA81C32FC" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_D209D469866EF4F1B7FF591AA81C6511" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/ConsolidatedStatementsOfChangesInEquityParenthetical" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_AEADA72611361EDC909544E5AC285A44" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_79B21F907AF7A46179C444E5AC184355" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_AEADA72611361EDC909544E5AC285A44" xlink:to="loc_us-gaap_StatementTable_79B21F907AF7A46179C444E5AC184355" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_7FE6568C7E4D3EA72A5944E5AC187E96" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_79B21F907AF7A46179C444E5AC184355" xlink:to="loc_us-gaap_StatementClassOfStockAxis_7FE6568C7E4D3EA72A5944E5AC187E96" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_A60011421876823D0D5D44E5AC18FB6F_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_7FE6568C7E4D3EA72A5944E5AC187E96" xlink:to="loc_us-gaap_ClassOfStockDomain_A60011421876823D0D5D44E5AC18FB6F_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_A60011421876823D0D5D44E5AC18FB6F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_7FE6568C7E4D3EA72A5944E5AC187E96" xlink:to="loc_us-gaap_ClassOfStockDomain_A60011421876823D0D5D44E5AC18FB6F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TreasuryStockMember" xlink:label="loc_us-gaap_TreasuryStockMember_8D33BA6D6C81A45BBC4344E5AC188150" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_A60011421876823D0D5D44E5AC18FB6F" xlink:to="loc_us-gaap_TreasuryStockMember_8D33BA6D6C81A45BBC4344E5AC188150" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_4C4B8D7041EBB7BACD3244E5AC2813D9" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_AEADA72611361EDC909544E5AC285A44" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_4C4B8D7041EBB7BACD3244E5AC2813D9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax_4459889344AEC10021A944E5AC29BDBD" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_AEADA72611361EDC909544E5AC285A44" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTax_4459889344AEC10021A944E5AC29BDBD" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeituresAndTaxObligationsSettledInShares" xlink:label="loc_hsc_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeituresAndTaxObligationsSettledInShares_FFF4B5CD52983257754B44E5AC29602E" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_AEADA72611361EDC909544E5AC285A44" xlink:to="loc_hsc_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeituresAndTaxObligationsSettledInShares_FFF4B5CD52983257754B44E5AC29602E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TreasuryStockSharesAcquired" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_D11ED67BD288B923E6BE44E5AC295282" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_AEADA72611361EDC909544E5AC285A44" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_D11ED67BD288B923E6BE44E5AC295282" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_VestingofPerformanceShares" xlink:label="loc_hsc_VestingofPerformanceShares_33C2D71B49B75671A49544E5AC29DA10" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_AEADA72611361EDC909544E5AC285A44" xlink:to="loc_hsc_VestingofPerformanceShares_33C2D71B49B75671A49544E5AC29DA10" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SharebasedCompensationArrangementbySharebasedPaymentAwardNonOptionEquityInstrumentsExercisedNet" xlink:label="loc_hsc_SharebasedCompensationArrangementbySharebasedPaymentAwardNonOptionEquityInstrumentsExercisedNet_2D1683B1FF9FDDF66DC744FCBA3A00EE" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_AEADA72611361EDC909544E5AC285A44" xlink:to="loc_hsc_SharebasedCompensationArrangementbySharebasedPaymentAwardNonOptionEquityInstrumentsExercisedNet_2D1683B1FF9FDDF66DC744FCBA3A00EE" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/ConsolidatedStatementsOfComprehensiveIncomeLoss" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/ConsolidatedStatementsOfComprehensiveIncomeLossParenthetical" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/ConsolidatedStatementsOfOperations" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_A6C27D83D014705D74B762F4F408BD75" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_StatementTable_A6C27D83D014705D74B762F4F408BD75" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis_49FDA7EF5E5F2B80E8F062F4F408F336" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_A6C27D83D014705D74B762F4F408BD75" xlink:to="loc_srt_ProductOrServiceAxis_49FDA7EF5E5F2B80E8F062F4F408F336" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_056C9A1258E87A7DC0A562F4F40C70E8_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_49FDA7EF5E5F2B80E8F062F4F408F336" xlink:to="loc_srt_ProductsAndServicesDomain_056C9A1258E87A7DC0A562F4F40C70E8_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_056C9A1258E87A7DC0A562F4F40C70E8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_49FDA7EF5E5F2B80E8F062F4F408F336" xlink:to="loc_srt_ProductsAndServicesDomain_056C9A1258E87A7DC0A562F4F40C70E8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ServiceMember" xlink:label="loc_us-gaap_ServiceMember_5B40F1613815B0BF509162F4F40C73F9" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_056C9A1258E87A7DC0A562F4F40C70E8" xlink:to="loc_us-gaap_ServiceMember_5B40F1613815B0BF509162F4F40C73F9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProductMember" xlink:label="loc_us-gaap_ProductMember_B47F3F165A1C1F01D44D62F4F40CF621" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_056C9A1258E87A7DC0A562F4F40C70E8" xlink:to="loc_us-gaap_ProductMember_B47F3F165A1C1F01D44D62F4F40CF621" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenuesAbstract" xlink:label="loc_us-gaap_RevenuesAbstract_CCE7AE7EF062E8839D9762F4F40C754F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_RevenuesAbstract_CCE7AE7EF062E8839D9762F4F40C754F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_A2F3D95E871136F1C5C562F4F40C45E3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_CCE7AE7EF062E8839D9762F4F40C754F" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_A2F3D95E871136F1C5C562F4F40C45E3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostsAndExpensesAbstract" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_5404252B0B552FDF52D062F4F40C0342" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_5404252B0B552FDF52D062F4F40C0342" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_4BB8ADC4406A058E146C62F4F40CB0C3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_5404252B0B552FDF52D062F4F40C0342" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_4BB8ADC4406A058E146C62F4F40CB0C3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_E9E75D1C89D24F9ACCFE62F4F40C99FB" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_5404252B0B552FDF52D062F4F40C0342" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_E9E75D1C89D24F9ACCFE62F4F40C99FB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_78628EBE3A9401E0333F62F4F40CA0F6" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_5404252B0B552FDF52D062F4F40C0342" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_78628EBE3A9401E0333F62F4F40CA0F6" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherOperatingIncomeExpenseNet" xlink:label="loc_us-gaap_OtherOperatingIncomeExpenseNet_7F922F5C3116E06B1D3862F4F40C4F2B" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_5404252B0B552FDF52D062F4F40C0342" xlink:to="loc_us-gaap_OtherOperatingIncomeExpenseNet_7F922F5C3116E06B1D3862F4F40C4F2B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="loc_us-gaap_CostsAndExpenses_8130DD8BE78ED2989B6662F4F410D351" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_5404252B0B552FDF52D062F4F40C0342" xlink:to="loc_us-gaap_CostsAndExpenses_8130DD8BE78ED2989B6662F4F410D351" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_B112DA5D094B446E3C9162F4F4102C9F" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_5404252B0B552FDF52D062F4F40C0342" xlink:to="loc_us-gaap_OperatingIncomeLoss_B112DA5D094B446E3C9162F4F4102C9F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest_9F4E91AD4069D5BF14DF62F4F4145806" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_InvestmentIncomeInterest_9F4E91AD4069D5BF14DF62F4F4145806" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_6849CAB6D3F6DEE76A4962F4F4141B8C" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_InterestExpense_6849CAB6D3F6DEE76A4962F4F4141B8C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionExpenseReversalOfExpenseNoncash" xlink:label="loc_us-gaap_PensionExpenseReversalOfExpenseNoncash_542B8A7634F1A032894662F4F41413ED" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_PensionExpenseReversalOfExpenseNoncash_542B8A7634F1A032894662F4F41413ED" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_8C1B1060C29C20F229A862F4F4143CF4" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_8C1B1060C29C20F229A862F4F4143CF4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_CD76D65A4BCA6C54155362F4F4142DF9" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_CD76D65A4BCA6C54155362F4F4142DF9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_1447B0CD0ACFDFF8BD1962F4F414CE8C" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_1447B0CD0ACFDFF8BD1962F4F414CE8C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_9B244AE3C718E98536AD62F4F414219A" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_9B244AE3C718E98536AD62F4F414219A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_A165D23701156F86A86862F4F41454A2" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_A165D23701156F86A86862F4F41454A2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAbstract" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAbstract_23BBA58BDDAC325B410A62F4F4148CAF" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAbstract_23BBA58BDDAC325B410A62F4F4148CAF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax" xlink:label="loc_us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax_BDD9E0A3AB90E918C23562F4F4144CA2" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAbstract_23BBA58BDDAC325B410A62F4F4148CAF" xlink:to="loc_us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax_BDD9E0A3AB90E918C23562F4F4144CA2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_C76E557886AC8497223F62F4F41496F7" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAbstract_23BBA58BDDAC325B410A62F4F4148CAF" xlink:to="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_C76E557886AC8497223F62F4F41496F7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation" xlink:label="loc_us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation_96AC01FED094923D7A4562F4F4147AD6" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAbstract_23BBA58BDDAC325B410A62F4F4148CAF" xlink:to="loc_us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation_96AC01FED094923D7A4562F4F4147AD6" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity_156219052F663E076C7C62F4F414FB78" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAbstract_23BBA58BDDAC325B410A62F4F4148CAF" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity_156219052F663E076C7C62F4F414FB78" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_ED31F515FD220941FD4462F4F4141F12" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_ProfitLoss_ED31F515FD220941FD4462F4F4141F12" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_9F336B788DCBB5B2AC9562F4F4146F07" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_9F336B788DCBB5B2AC9562F4F4146F07" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_C85F2D2A92554BA0517762F4F418B1BC" xlink:type="locator"/>
<link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_NetIncomeLoss_C85F2D2A92554BA0517762F4F418B1BC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeAmountsAttributableToReportingEntityDisclosuresAbstract" xlink:label="loc_us-gaap_IncomeAmountsAttributableToReportingEntityDisclosuresAbstract_3AE6672A8AE99BB9828662F4F4183C4E" xlink:type="locator"/>
<link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_IncomeAmountsAttributableToReportingEntityDisclosuresAbstract_3AE6672A8AE99BB9828662F4F4183C4E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperations" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperations_963F4B3A01DEC937DE9E62F4F41886A8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeAmountsAttributableToReportingEntityDisclosuresAbstract_3AE6672A8AE99BB9828662F4F4183C4E" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperations_963F4B3A01DEC937DE9E62F4F41886A8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_B4D4F813E79EFD3B4D3862F4F418B36B" xlink:type="locator"/>
<link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_B4D4F813E79EFD3B4D3862F4F418B36B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareBasicAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAbstract_3310FDA99B5F8DAEB9AD62F4F4181AB9" xlink:type="locator"/>
<link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_EarningsPerShareBasicAbstract_3310FDA99B5F8DAEB9AD62F4F4181AB9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_BF7535E8596066F67A9662F4F4182EDA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_3310FDA99B5F8DAEB9AD62F4F4181AB9" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_BF7535E8596066F67A9662F4F4182EDA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_3AA05A823FED49C79C7B62F4F418DEE2" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_3310FDA99B5F8DAEB9AD62F4F4181AB9" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_3AA05A823FED49C79C7B62F4F418DEE2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="loc_us-gaap_EarningsPerShareBasic_7AE1E53E300201879C6362F4F418E4E0" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_3310FDA99B5F8DAEB9AD62F4F4181AB9" xlink:to="loc_us-gaap_EarningsPerShareBasic_7AE1E53E300201879C6362F4F418E4E0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_505C46CBE6D8A1B7B43662F4F4181CE9" xlink:type="locator"/>
<link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_505C46CBE6D8A1B7B43662F4F4181CE9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareDilutedAbstract" xlink:label="loc_us-gaap_EarningsPerShareDilutedAbstract_90551118EC6B35A1829C62F4F41840CB" xlink:type="locator"/>
<link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_31701A28C53E556A0E3862F4F40CAAB7" xlink:to="loc_us-gaap_EarningsPerShareDilutedAbstract_90551118EC6B35A1829C62F4F41840CB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_C0959480692AA61CF41862F4F418C451" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_90551118EC6B35A1829C62F4F41840CB" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_C0959480692AA61CF41862F4F418C451" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare_CEAC1F803CDB292ED4DE62F4F41810CF" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_90551118EC6B35A1829C62F4F41840CB" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare_CEAC1F803CDB292ED4DE62F4F41810CF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="loc_us-gaap_EarningsPerShareDiluted_8AD8F8CC7A6D4B30932162F4F4186414" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareDilutedAbstract_90551118EC6B35A1829C62F4F41840CB" xlink:to="loc_us-gaap_EarningsPerShareDiluted_8AD8F8CC7A6D4B30932162F4F4186414" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/DebtAndCreditAgreements" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/DebtAndCreditAgreementsNarrativeDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_7578CCF1BED3C5059814591AA618CACA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_7578CCF1BED3C5059814591AA618CACA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_MaturityPeriodAxis" xlink:label="loc_hsc_MaturityPeriodAxis_E1A8DE2153B2B274A731591AA6184F7C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_7578CCF1BED3C5059814591AA618CACA" xlink:to="loc_hsc_MaturityPeriodAxis_E1A8DE2153B2B274A731591AA6184F7C" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_MaturityPeriodDomain" xlink:label="loc_hsc_MaturityPeriodDomain_EEBD3CD8690CD7CBDAAB591AA6186569_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_hsc_MaturityPeriodAxis_E1A8DE2153B2B274A731591AA6184F7C" xlink:to="loc_hsc_MaturityPeriodDomain_EEBD3CD8690CD7CBDAAB591AA6186569_default" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_MaturityPeriodDomain" xlink:label="loc_hsc_MaturityPeriodDomain_EEBD3CD8690CD7CBDAAB591AA6186569" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_hsc_MaturityPeriodAxis_E1A8DE2153B2B274A731591AA6184F7C" xlink:to="loc_hsc_MaturityPeriodDomain_EEBD3CD8690CD7CBDAAB591AA6186569" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_1888AF2F1ABD419323A8591AA618D1C2" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_7578CCF1BED3C5059814591AA618CACA" xlink:to="loc_us-gaap_CreditFacilityAxis_1888AF2F1ABD419323A8591AA618D1C2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_5FBA7EE97F57E573B0AE591AA6182B69_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_1888AF2F1ABD419323A8591AA618D1C2" xlink:to="loc_us-gaap_CreditFacilityDomain_5FBA7EE97F57E573B0AE591AA6182B69_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_5FBA7EE97F57E573B0AE591AA6182B69" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_1888AF2F1ABD419323A8591AA618D1C2" xlink:to="loc_us-gaap_CreditFacilityDomain_5FBA7EE97F57E573B0AE591AA6182B69" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_6A50282E2F55F3365910591AA6187E77" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_5FBA7EE97F57E573B0AE591AA6182B69" xlink:to="loc_us-gaap_LineOfCreditMember_6A50282E2F55F3365910591AA6187E77" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_BAB3C67DE4A6E2E997B5591AA61857F4" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_5FBA7EE97F57E573B0AE591AA6182B69" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_BAB3C67DE4A6E2E997B5591AA61857F4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_02C92C5B6A7B2C46268C591AA6182317" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_7578CCF1BED3C5059814591AA618CACA" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_02C92C5B6A7B2C46268C591AA6182317" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_062829403FABAEF22CDE591AA61892BE_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_02C92C5B6A7B2C46268C591AA6182317" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_062829403FABAEF22CDE591AA61892BE_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_062829403FABAEF22CDE591AA61892BE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_02C92C5B6A7B2C46268C591AA6182317" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_062829403FABAEF22CDE591AA61892BE" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TermLoanMember" xlink:label="loc_hsc_TermLoanMember_1AED31691FBD19571E91591AA6180DBA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_062829403FABAEF22CDE591AA61892BE" xlink:to="loc_hsc_TermLoanMember_1AED31691FBD19571E91591AA6180DBA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_7FDA0E1B9A0DD6A05772591AA618B031" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_062829403FABAEF22CDE591AA61892BE" xlink:to="loc_us-gaap_SeniorNotesMember_7FDA0E1B9A0DD6A05772591AA618B031" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SeniorSecuredCreditFacilitiesMember" xlink:label="loc_hsc_SeniorSecuredCreditFacilitiesMember_E97BAA3E05C814BC3429591AA6185833" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_062829403FABAEF22CDE591AA61892BE" xlink:to="loc_hsc_SeniorSecuredCreditFacilitiesMember_E97BAA3E05C814BC3429591AA6185833" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_2E116C507B9602F754E4591AA6186EBB" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_062829403FABAEF22CDE591AA61892BE" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_2E116C507B9602F754E4591AA6186EBB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnsecuredDebtMember" xlink:label="loc_us-gaap_UnsecuredDebtMember_A971C4EFDCD3EC1E83F5591AA6186EBC" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_062829403FABAEF22CDE591AA61892BE" xlink:to="loc_us-gaap_UnsecuredDebtMember_A971C4EFDCD3EC1E83F5591AA6186EBC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BridgeLoanMember" xlink:label="loc_us-gaap_BridgeLoanMember_52867FDD1247984FDBF7591AA61811F0" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_062829403FABAEF22CDE591AA61892BE" xlink:to="loc_us-gaap_BridgeLoanMember_52867FDD1247984FDBF7591AA61811F0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_3CEEE48B25F51895BE6B591AA61810BF" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_7578CCF1BED3C5059814591AA618CACA" xlink:to="loc_us-gaap_DebtInstrumentAxis_3CEEE48B25F51895BE6B591AA61810BF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_DE5D67FB336DCA8E7893591AA61831AD_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_3CEEE48B25F51895BE6B591AA61810BF" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_DE5D67FB336DCA8E7893591AA61831AD_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_DE5D67FB336DCA8E7893591AA61831AD" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_3CEEE48B25F51895BE6B591AA61810BF" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_DE5D67FB336DCA8E7893591AA61831AD" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SeniorUnsecuredNotes5.75Due2027Member" xlink:label="loc_hsc_SeniorUnsecuredNotes5.75Due2027Member_C5FE59D144CE5FA33EA2591AA6186B5E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_DE5D67FB336DCA8E7893591AA61831AD" xlink:to="loc_hsc_SeniorUnsecuredNotes5.75Due2027Member_C5FE59D144CE5FA33EA2591AA6186B5E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_NewCreditFacilityMember" xlink:label="loc_hsc_NewCreditFacilityMember_2E36E4CE843DA784CBF8591AA61811A6" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_DE5D67FB336DCA8E7893591AA61831AD" xlink:to="loc_hsc_NewCreditFacilityMember_2E36E4CE843DA784CBF8591AA61811A6" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_Notes5Point75PercentDue15May2018Member" xlink:label="loc_hsc_Notes5Point75PercentDue15May2018Member_AD4D2092B9A265CAEC72591AA61859EB" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_DE5D67FB336DCA8E7893591AA61831AD" xlink:to="loc_hsc_Notes5Point75PercentDue15May2018Member_AD4D2092B9A265CAEC72591AA61859EB" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TermLoanFacilityFixedRateMember" xlink:label="loc_hsc_TermLoanFacilityFixedRateMember_819798929E44D0964D41591AA61842FB" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_DE5D67FB336DCA8E7893591AA61831AD" xlink:to="loc_hsc_TermLoanFacilityFixedRateMember_819798929E44D0964D41591AA61842FB" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SeniorSecuredCreditFacilitiesMember" xlink:label="loc_hsc_SeniorSecuredCreditFacilitiesMember_F48E728FEC3C6DDC1298591AA618C53B" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_DE5D67FB336DCA8E7893591AA61831AD" xlink:to="loc_hsc_SeniorSecuredCreditFacilitiesMember_F48E728FEC3C6DDC1298591AA618C53B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_7FD1EB516A7A52CF70F9591AA618D429" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_7578CCF1BED3C5059814591AA618CACA" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_7FD1EB516A7A52CF70F9591AA618D429" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_CAE2C83FDF4DE213E5A7591AA618ED37_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_7FD1EB516A7A52CF70F9591AA618D429" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_CAE2C83FDF4DE213E5A7591AA618ED37_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_CAE2C83FDF4DE213E5A7591AA618ED37" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_7FD1EB516A7A52CF70F9591AA618D429" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_CAE2C83FDF4DE213E5A7591AA618ED37" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_C52EEE6AD554BBD0FA04591AA6185A06" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_7578CCF1BED3C5059814591AA618CACA" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_C52EEE6AD554BBD0FA04591AA6185A06" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_DCE298D5CE623EFBCB0A591AA61836F1_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_C52EEE6AD554BBD0FA04591AA6185A06" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_DCE298D5CE623EFBCB0A591AA61836F1_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_DCE298D5CE623EFBCB0A591AA61836F1" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_C52EEE6AD554BBD0FA04591AA6185A06" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_DCE298D5CE623EFBCB0A591AA61836F1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_31BB97959F202E71230B591AA618669E" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_7578CCF1BED3C5059814591AA618CACA" xlink:to="loc_srt_RangeAxis_31BB97959F202E71230B591AA618669E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_E3C0AFE2AD1E9359A918591AA6185D19_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_31BB97959F202E71230B591AA618669E" xlink:to="loc_srt_RangeMember_E3C0AFE2AD1E9359A918591AA6185D19_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_E3C0AFE2AD1E9359A918591AA6185D19" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_31BB97959F202E71230B591AA618669E" xlink:to="loc_srt_RangeMember_E3C0AFE2AD1E9359A918591AA6185D19" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_B8FB9B1A97E3C30A724A591AA618C2B4" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_E3C0AFE2AD1E9359A918591AA6185D19" xlink:to="loc_srt_MinimumMember_B8FB9B1A97E3C30A724A591AA618C2B4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_B6AF95A59ACF06F8B510591AA618C0D7" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_E3C0AFE2AD1E9359A918591AA6185D19" xlink:to="loc_srt_MaximumMember_B6AF95A59ACF06F8B510591AA618C0D7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="loc_us-gaap_VariableRateAxis_2861FFC86A3327987AF8591AA618C8A0" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_7578CCF1BED3C5059814591AA618CACA" xlink:to="loc_us-gaap_VariableRateAxis_2861FFC86A3327987AF8591AA618C8A0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_09B760401828CCCA1D94591AA6187979_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_2861FFC86A3327987AF8591AA618C8A0" xlink:to="loc_us-gaap_VariableRateDomain_09B760401828CCCA1D94591AA6187979_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_09B760401828CCCA1D94591AA6187979" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_2861FFC86A3327987AF8591AA618C8A0" xlink:to="loc_us-gaap_VariableRateDomain_09B760401828CCCA1D94591AA6187979" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BaseRateMember" xlink:label="loc_us-gaap_BaseRateMember_04F9362A2290601C5537591AA618BFF3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_09B760401828CCCA1D94591AA6187979" xlink:to="loc_us-gaap_BaseRateMember_04F9362A2290601C5537591AA618BFF3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_90F7889BB75BFFA9B382591AA6184E04" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_09B760401828CCCA1D94591AA6187979" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_90F7889BB75BFFA9B382591AA6184E04" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_StatementScenarioAxis" xlink:label="loc_srt_StatementScenarioAxis_33E8EAD842E1B9A33B31591AA618CE79" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_7578CCF1BED3C5059814591AA618CACA" xlink:to="loc_srt_StatementScenarioAxis_33E8EAD842E1B9A33B31591AA618CE79" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srt_ScenarioUnspecifiedDomain_36AFD188BA1D8A03D33E591AA618895F_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_33E8EAD842E1B9A33B31591AA618CE79" xlink:to="loc_srt_ScenarioUnspecifiedDomain_36AFD188BA1D8A03D33E591AA618895F_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srt_ScenarioUnspecifiedDomain_36AFD188BA1D8A03D33E591AA618895F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_33E8EAD842E1B9A33B31591AA618CE79" xlink:to="loc_srt_ScenarioUnspecifiedDomain_36AFD188BA1D8A03D33E591AA618895F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ScenarioForecastMember" xlink:label="loc_srt_ScenarioForecastMember_6073775009B980CFCBB2591AA61866AF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_36AFD188BA1D8A03D33E591AA618895F" xlink:to="loc_srt_ScenarioForecastMember_6073775009B980CFCBB2591AA61866AF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestPaid" xlink:label="loc_us-gaap_InterestPaid_EFC84CC8537909BEB1D0591AA618DD5D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_InterestPaid_EFC84CC8537909BEB1D0591AA618DD5D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_F62D32D294F2C358ED38591AA618A6AD" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_F62D32D294F2C358ED38591AA618A6AD" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityIncreaseDecreaseForPeriodNet" xlink:label="loc_us-gaap_LineOfCreditFacilityIncreaseDecreaseForPeriodNet_1017B6FAF1FFDE6AEF96591AA618F91D" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_LineOfCreditFacilityIncreaseDecreaseForPeriodNet_1017B6FAF1FFDE6AEF96591AA618F91D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_34F3B878B3D43FB8D2C5591AA6184F33" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_34F3B878B3D43FB8D2C5591AA6184F33" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DebtInstrumentCovenantMinimumConsolidatedInterestCoverageRatioNumerator" xlink:label="loc_hsc_DebtInstrumentCovenantMinimumConsolidatedInterestCoverageRatioNumerator_414C9D7381213552A4C1591AA61852D4" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_hsc_DebtInstrumentCovenantMinimumConsolidatedInterestCoverageRatioNumerator_414C9D7381213552A4C1591AA61852D4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainsLossesOnRestructuringOfDebt" xlink:label="loc_us-gaap_GainsLossesOnRestructuringOfDebt_911B09ADC78A5EC398A8591AA6182C19" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_GainsLossesOnRestructuringOfDebt_911B09ADC78A5EC398A8591AA6182C19" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredFinanceCostsGross" xlink:label="loc_us-gaap_DeferredFinanceCostsGross_9556BA3785CBD505753F591AA618E564" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_DeferredFinanceCostsGross_9556BA3785CBD505753F591AA618E564" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DebtInstrumentBasisSpreadOnVariableRateFloor" xlink:label="loc_hsc_DebtInstrumentBasisSpreadOnVariableRateFloor_E082A0FF3F29483E33F5591AA6187AB3" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_hsc_DebtInstrumentBasisSpreadOnVariableRateFloor_E082A0FF3F29483E33F5591AA6187AB3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_2CDD02C6A2458510FF7A591AA618121D" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_2CDD02C6A2458510FF7A591AA618121D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RepaymentsOfDebt" xlink:label="loc_us-gaap_RepaymentsOfDebt_1540AEFDE6625BD5CAD4591AA6180A25" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_RepaymentsOfDebt_1540AEFDE6625BD5CAD4591AA6180A25" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_6C07FEF9CBFB0456D44A591AA61808B3" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_6C07FEF9CBFB0456D44A591AA61808B3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WriteOffOfDeferredDebtIssuanceCost" xlink:label="loc_us-gaap_WriteOffOfDeferredDebtIssuanceCost_2DBBA83C6DAF9DC63A06591AA6182301" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_WriteOffOfDeferredDebtIssuanceCost_2DBBA83C6DAF9DC63A06591AA6182301" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_A0112F076928182C90B7591AA618611F" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_A0112F076928182C90B7591AA618611F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_45C407D2A52933C91D2A591AA618D946" xlink:type="locator"/>
<link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_45C407D2A52933C91D2A591AA618D946" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShortTermBorrowings" xlink:label="loc_us-gaap_ShortTermBorrowings_74414767D5F07A2E1B12591AA6182B6E" xlink:type="locator"/>
<link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_ShortTermBorrowings_74414767D5F07A2E1B12591AA6182B6E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShortTermDebtWeightedAverageInterestRate" xlink:label="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_40EA92D34CFC759A879C591AA6186F95" xlink:type="locator"/>
<link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A03A0702EC8D574F9FE9591AA6189106" xlink:to="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_40EA92D34CFC759A879C591AA6186F95" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/DebtAndCreditAgreementsOutstandingAmountsUnderRevolvingCreditFacilityDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_88541F6B126B211AA82641A717B5FDAA" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_46352D1537FBD2BCC01741A717ADA3E0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_88541F6B126B211AA82641A717B5FDAA" xlink:to="loc_us-gaap_DebtInstrumentTable_46352D1537FBD2BCC01741A717ADA3E0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_08CCD5570BE50F07AA1141A81186318D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_46352D1537FBD2BCC01741A717ADA3E0" xlink:to="loc_us-gaap_CreditFacilityAxis_08CCD5570BE50F07AA1141A81186318D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_919B4ACC4DDEA5FBF2C841A81298DE35_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_08CCD5570BE50F07AA1141A81186318D" xlink:to="loc_us-gaap_CreditFacilityDomain_919B4ACC4DDEA5FBF2C841A81298DE35_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_919B4ACC4DDEA5FBF2C841A81298DE35" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_08CCD5570BE50F07AA1141A81186318D" xlink:to="loc_us-gaap_CreditFacilityDomain_919B4ACC4DDEA5FBF2C841A81298DE35" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_EB1EB413802FC800A65941A8121944C5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_919B4ACC4DDEA5FBF2C841A81298DE35" xlink:to="loc_us-gaap_LineOfCreditMember_EB1EB413802FC800A65941A8121944C5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_69A33102C4C00AB06B5041A7CBCD00AE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_88541F6B126B211AA82641A717B5FDAA" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_69A33102C4C00AB06B5041A7CBCD00AE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_EB879AEB728D86FCC85341A740BCA46A" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_88541F6B126B211AA82641A717B5FDAA" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_EB879AEB728D86FCC85341A740BCA46A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCredit" xlink:label="loc_us-gaap_LineOfCredit_2D9810B7CA97DE6557A041A8DA9E13FD" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_88541F6B126B211AA82641A717B5FDAA" xlink:to="loc_us-gaap_LineOfCredit_2D9810B7CA97DE6557A041A8DA9E13FD" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_C128BC90A97E1B2E12E041A8DAADF761" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_88541F6B126B211AA82641A717B5FDAA" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_C128BC90A97E1B2E12E041A8DAADF761" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/DebtAndCreditAgreementsScheduleOfLongTermDebtDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_D5E0518C4E92A7CA003459EC75A42E9B" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_23DA38119011ACBCDBD459EC75A0A54E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_D5E0518C4E92A7CA003459EC75A42E9B" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_23DA38119011ACBCDBD459EC75A0A54E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_349388ACDCF8B1F4D41059EC75A060F7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_23DA38119011ACBCDBD459EC75A0A54E" xlink:to="loc_us-gaap_DebtInstrumentAxis_349388ACDCF8B1F4D41059EC75A060F7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_C8E3698D42825E7314C159EC75A1E2D0_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_349388ACDCF8B1F4D41059EC75A060F7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_C8E3698D42825E7314C159EC75A1E2D0_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_C8E3698D42825E7314C159EC75A1E2D0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_349388ACDCF8B1F4D41059EC75A060F7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_C8E3698D42825E7314C159EC75A1E2D0" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_Notes5Point75PercentDue15May2018Member" xlink:label="loc_hsc_Notes5Point75PercentDue15May2018Member_32A180CF14F756510B8A59EC75A1BB46" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_C8E3698D42825E7314C159EC75A1E2D0" xlink:to="loc_hsc_Notes5Point75PercentDue15May2018Member_32A180CF14F756510B8A59EC75A1BB46" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_5A95B4A7CBB2C7D1A26459EC75A148B8" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_23DA38119011ACBCDBD459EC75A0A54E" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_5A95B4A7CBB2C7D1A26459EC75A148B8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_8B61523F5DBC4E1EEAC959EC75A12D06_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_5A95B4A7CBB2C7D1A26459EC75A148B8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_8B61523F5DBC4E1EEAC959EC75A12D06_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_8B61523F5DBC4E1EEAC959EC75A12D06" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_5A95B4A7CBB2C7D1A26459EC75A148B8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_8B61523F5DBC4E1EEAC959EC75A12D06" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SeniorSecuredCreditFacilitiesMember" xlink:label="loc_hsc_SeniorSecuredCreditFacilitiesMember_70FBB81B2C5A50C1CC4459EC75A27008" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_8B61523F5DBC4E1EEAC959EC75A12D06" xlink:to="loc_hsc_SeniorSecuredCreditFacilitiesMember_70FBB81B2C5A50C1CC4459EC75A27008" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TermLoanMember" xlink:label="loc_hsc_TermLoanMember_2B91817D25DF1C4E256B59EC75A2B3D8" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_8B61523F5DBC4E1EEAC959EC75A12D06" xlink:to="loc_hsc_TermLoanMember_2B91817D25DF1C4E256B59EC75A2B3D8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_B80561F863D293E05DE659EC75A29DC2" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_8B61523F5DBC4E1EEAC959EC75A12D06" xlink:to="loc_us-gaap_SeniorNotesMember_B80561F863D293E05DE659EC75A29DC2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_000FDAA8C88BB4F44C0959EC75A2E513" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_8B61523F5DBC4E1EEAC959EC75A12D06" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_000FDAA8C88BB4F44C0959EC75A2E513" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityAxis" xlink:label="loc_us-gaap_LineOfCreditFacilityAxis_4FE423A5A3B3346694A459EC75A207F5" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_23DA38119011ACBCDBD459EC75A0A54E" xlink:to="loc_us-gaap_LineOfCreditFacilityAxis_4FE423A5A3B3346694A459EC75A207F5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_E614218A0704142D469959EC75A33CCB_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_4FE423A5A3B3346694A459EC75A207F5" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_E614218A0704142D469959EC75A33CCB_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityLenderDomain" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_E614218A0704142D469959EC75A33CCB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_4FE423A5A3B3346694A459EC75A207F5" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_E614218A0704142D469959EC75A33CCB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_76ABFD5A5731D83EB08F59EC75A36D1A" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_23DA38119011ACBCDBD459EC75A0A54E" xlink:to="loc_us-gaap_CreditFacilityAxis_76ABFD5A5731D83EB08F59EC75A36D1A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_2735ED72B62B126245AC59EC75A3A5D9_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_76ABFD5A5731D83EB08F59EC75A36D1A" xlink:to="loc_us-gaap_CreditFacilityDomain_2735ED72B62B126245AC59EC75A3A5D9_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_2735ED72B62B126245AC59EC75A3A5D9" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_76ABFD5A5731D83EB08F59EC75A36D1A" xlink:to="loc_us-gaap_CreditFacilityDomain_2735ED72B62B126245AC59EC75A3A5D9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_1F2EB1B231D99CFA0C9F59EC75A3F870" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_2735ED72B62B126245AC59EC75A3A5D9" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_1F2EB1B231D99CFA0C9F59EC75A3F870" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_ACBE1BDD5ED71E1F6E3459EC75A4A0FA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_D5E0518C4E92A7CA003459EC75A42E9B" xlink:to="loc_us-gaap_LongTermDebt_ACBE1BDD5ED71E1F6E3459EC75A4A0FA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_6BF2AC593D124E74365259EC75A4B3F4" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_D5E0518C4E92A7CA003459EC75A42E9B" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_6BF2AC593D124E74365259EC75A4B3F4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredFinanceCostsNoncurrentNet" xlink:label="loc_us-gaap_DeferredFinanceCostsNoncurrentNet_2F9E978983F5FA7EC35459EC75A48843" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_D5E0518C4E92A7CA003459EC75A42E9B" xlink:to="loc_us-gaap_DeferredFinanceCostsNoncurrentNet_2F9E978983F5FA7EC35459EC75A48843" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent_934A1B879FDF02B82ED259EC75A4527D" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_D5E0518C4E92A7CA003459EC75A42E9B" xlink:to="loc_us-gaap_LongTermDebtCurrent_934A1B879FDF02B82ED259EC75A4527D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_1664522B3AC0F33E887D59EC75A53BA3" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_D5E0518C4E92A7CA003459EC75A42E9B" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_1664522B3AC0F33E887D59EC75A53BA3" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/DebtAndCreditAgreementsScheduleOfMaturitiesOfLongTermDebtDetails" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/DebtAndCreditAgreementsTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/DocumentAndEntityInformation" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/EmployeeBenefitPlans" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/EmployeeBenefitPlansDetails" xlink:type="extended">
<link:loc xlink:href="hsc-20191231.xsd#hsc_PensionAndPostretirementPlansLineItems" xlink:label="loc_hsc_PensionAndPostretirementPlansLineItems_CBF433DD88B07A925F6C41E01FB52BBF" xlink:type="locator"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ScheduleOfPensionAndPostretirementPlansTable" xlink:label="loc_hsc_ScheduleOfPensionAndPostretirementPlansTable_6EF3134EBE74BC1331D541E01FA49B2A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_hsc_PensionAndPostretirementPlansLineItems_CBF433DD88B07A925F6C41E01FB52BBF" xlink:to="loc_hsc_ScheduleOfPensionAndPostretirementPlansTable_6EF3134EBE74BC1331D541E01FA49B2A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationAxis" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationAxis_36F9E13BE094FC7EADED41E01FA4BA74" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_hsc_ScheduleOfPensionAndPostretirementPlansTable_6EF3134EBE74BC1331D541E01FA49B2A" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationAxis_36F9E13BE094FC7EADED41E01FA4BA74" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationDomain" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_B3645820A7A4392518A941E01FA428E8_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_36F9E13BE094FC7EADED41E01FA4BA74" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_B3645820A7A4392518A941E01FA428E8_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationDomain" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_B3645820A7A4392518A941E01FA428E8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_36F9E13BE094FC7EADED41E01FA4BA74" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_B3645820A7A4392518A941E01FA428E8" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_US" xlink:label="loc_country_US_161975A3BF6EBD27E0FE41E01FA4105F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_B3645820A7A4392518A941E01FA428E8" xlink:to="loc_country_US_161975A3BF6EBD27E0FE41E01FA4105F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignPlanMember" xlink:label="loc_us-gaap_ForeignPlanMember_D8640C91A5546569141441E01FA4DBAD" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_B3645820A7A4392518A941E01FA428E8" xlink:to="loc_us-gaap_ForeignPlanMember_D8640C91A5546569141441E01FA4DBAD" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_CD7EDB741676F070620A41E01FA45F29" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_hsc_ScheduleOfPensionAndPostretirementPlansTable_6EF3134EBE74BC1331D541E01FA49B2A" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_CD7EDB741676F070620A41E01FA45F29" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_C02008236F9382C0BA9641E01FA4B71C_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_CD7EDB741676F070620A41E01FA45F29" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_C02008236F9382C0BA9641E01FA4B71C_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_C02008236F9382C0BA9641E01FA4B71C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_CD7EDB741676F070620A41E01FA45F29" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_C02008236F9382C0BA9641E01FA4B71C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_FEE1A6B631744149930E41E01FA4066A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_C02008236F9382C0BA9641E01FA4B71C" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_FEE1A6B631744149930E41E01FA4066A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MultiemployerPlanTypeAxis" xlink:label="loc_us-gaap_MultiemployerPlanTypeAxis_390A484AD6629165D54741E01FA461EE" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_hsc_ScheduleOfPensionAndPostretirementPlansTable_6EF3134EBE74BC1331D541E01FA49B2A" xlink:to="loc_us-gaap_MultiemployerPlanTypeAxis_390A484AD6629165D54741E01FA461EE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MultiemployerPlansTypeDomain" xlink:label="loc_us-gaap_MultiemployerPlansTypeDomain_72D5E67F770216E06CF341E01FB4F1CD_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MultiemployerPlanTypeAxis_390A484AD6629165D54741E01FA461EE" xlink:to="loc_us-gaap_MultiemployerPlansTypeDomain_72D5E67F770216E06CF341E01FB4F1CD_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MultiemployerPlansTypeDomain" xlink:label="loc_us-gaap_MultiemployerPlansTypeDomain_72D5E67F770216E06CF341E01FB4F1CD" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MultiemployerPlanTypeAxis_390A484AD6629165D54741E01FA461EE" xlink:to="loc_us-gaap_MultiemployerPlansTypeDomain_72D5E67F770216E06CF341E01FB4F1CD" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MultiemployerPlansPensionMember" xlink:label="loc_us-gaap_MultiemployerPlansPensionMember_DABA38988CAFF953AA1441E01FB43799" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MultiemployerPlansTypeDomain_72D5E67F770216E06CF341E01FB4F1CD" xlink:to="loc_us-gaap_MultiemployerPlansPensionMember_DABA38988CAFF953AA1441E01FB43799" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_F2681DAD34A08246EA1641E01FB4995C" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_hsc_ScheduleOfPensionAndPostretirementPlansTable_6EF3134EBE74BC1331D541E01FA49B2A" xlink:to="loc_srt_RangeAxis_F2681DAD34A08246EA1641E01FB4995C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_9F1C6946FA99D2B0081441E01FB4DE4D_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_F2681DAD34A08246EA1641E01FB4995C" xlink:to="loc_srt_RangeMember_9F1C6946FA99D2B0081441E01FB4DE4D_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_9F1C6946FA99D2B0081441E01FB4DE4D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_F2681DAD34A08246EA1641E01FB4995C" xlink:to="loc_srt_RangeMember_9F1C6946FA99D2B0081441E01FB4DE4D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_8F76EC8160882C7263AA41E01FB5DDF5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9F1C6946FA99D2B0081441E01FB4DE4D" xlink:to="loc_srt_MaximumMember_8F76EC8160882C7263AA41E01FB5DDF5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedContributionPensionAndOtherPostretirementPlansDisclosureAbstract" xlink:label="loc_us-gaap_DefinedContributionPensionAndOtherPostretirementPlansDisclosureAbstract_90A123B6D4393996EAA941E01FB5096C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_PensionAndPostretirementPlansLineItems_CBF433DD88B07A925F6C41E01FB52BBF" xlink:to="loc_us-gaap_DefinedContributionPensionAndOtherPostretirementPlansDisclosureAbstract_90A123B6D4393996EAA941E01FB5096C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_2083E2CC4D607DA8664241E01FB5C167" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedContributionPensionAndOtherPostretirementPlansDisclosureAbstract_90A123B6D4393996EAA941E01FB5096C" xlink:to="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_2083E2CC4D607DA8664241E01FB5C167" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount_D8090B1542F8EB62405441E01FB588D8" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedContributionPensionAndOtherPostretirementPlansDisclosureAbstract_90A123B6D4393996EAA941E01FB5096C" xlink:to="loc_us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount_D8090B1542F8EB62405441E01FB588D8" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedContributionPlanInternationalEmployerContributionForInsuranceAndAdministrativeCostsPercentage" xlink:label="loc_hsc_DefinedContributionPlanInternationalEmployerContributionForInsuranceAndAdministrativeCostsPercentage_C4270AF07B460A6E252941E01FB5E8DB" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedContributionPensionAndOtherPostretirementPlansDisclosureAbstract_90A123B6D4393996EAA941E01FB5096C" xlink:to="loc_hsc_DefinedContributionPlanInternationalEmployerContributionForInsuranceAndAdministrativeCostsPercentage_C4270AF07B460A6E252941E01FB5E8DB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_3AAB86B5E96A4C72C81C41E01FB5C04F" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_PensionAndPostretirementPlansLineItems_CBF433DD88B07A925F6C41E01FB52BBF" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_3AAB86B5E96A4C72C81C41E01FB5C04F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_AE29782CD4BBEFE797E741E01FB5434E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_3AAB86B5E96A4C72C81C41E01FB5C04F" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_AE29782CD4BBEFE797E741E01FB5434E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_A79D0F439B329197D03A41E01FB5D8DF" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_3AAB86B5E96A4C72C81C41E01FB5C04F" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_A79D0F439B329197D03A41E01FB5D8DF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_5CEC9DD9639DC7D27D2D41E01FB533F8" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_3AAB86B5E96A4C72C81C41E01FB5C04F" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_5CEC9DD9639DC7D27D2D41E01FB533F8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_DBDC2FFB81D4569A562841E01FB524EB" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_3AAB86B5E96A4C72C81C41E01FB5C04F" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_DBDC2FFB81D4569A562841E01FB524EB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_D744891589787C3F879141E01FB5ACA2" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_3AAB86B5E96A4C72C81C41E01FB5C04F" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_D744891589787C3F879141E01FB5ACA2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1" xlink:label="loc_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1_55539CCFA34561324D6E41E01FB5CAD3" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_3AAB86B5E96A4C72C81C41E01FB5C04F" xlink:to="loc_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1_55539CCFA34561324D6E41E01FB5CAD3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_42C4D97936563216A27241E01FB5CC8F" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_PensionAndPostretirementPlansLineItems_CBF433DD88B07A925F6C41E01FB52BBF" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_42C4D97936563216A27241E01FB5CC8F" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_MultiemployerPlanCostRecognized" xlink:label="loc_hsc_MultiemployerPlanCostRecognized_20D3FFCBE70505D9872F41E01FB5C4B7" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_PensionAndPostretirementPlansLineItems_CBF433DD88B07A925F6C41E01FB52BBF" xlink:to="loc_hsc_MultiemployerPlanCostRecognized_20D3FFCBE70505D9872F41E01FB5C4B7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedContributionPlanCostRecognized" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized_1768E7E78ABF23E3D6ED41E01FB589E2" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_PensionAndPostretirementPlansLineItems_CBF433DD88B07A925F6C41E01FB52BBF" xlink:to="loc_us-gaap_DefinedContributionPlanCostRecognized_1768E7E78ABF23E3D6ED41E01FB589E2" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_NetPeriodPensionCostsDomestic" xlink:label="loc_hsc_NetPeriodPensionCostsDomestic_CF87B1EDB7E735E8940041E01FB5BC7A" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_PensionAndPostretirementPlansLineItems_CBF433DD88B07A925F6C41E01FB52BBF" xlink:to="loc_hsc_NetPeriodPensionCostsDomestic_CF87B1EDB7E735E8940041E01FB5BC7A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_NetPeriodPensionCostsForeign" xlink:label="loc_hsc_NetPeriodPensionCostsForeign_F97A09A4D5906480BCFA41E01FB5F3B6" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_PensionAndPostretirementPlansLineItems_CBF433DD88B07A925F6C41E01FB52BBF" xlink:to="loc_hsc_NetPeriodPensionCostsForeign_F97A09A4D5906480BCFA41E01FB5F3B6" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/EmployeeBenefitPlansDetails2" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_D8EF84B1F6385E8E27235993E2AEE267" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_2FE7A9E41823CB55301B5993E2A74972" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_D8EF84B1F6385E8E27235993E2AEE267" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_2FE7A9E41823CB55301B5993E2A74972" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationAxis" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationAxis_57AF644CC8C08EE48C135993E2A7840E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_2FE7A9E41823CB55301B5993E2A74972" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationAxis_57AF644CC8C08EE48C135993E2A7840E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationDomain" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_FDE5172D42A5E65117A85993E2A76693_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_57AF644CC8C08EE48C135993E2A7840E" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_FDE5172D42A5E65117A85993E2A76693_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationDomain" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_FDE5172D42A5E65117A85993E2A76693" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_57AF644CC8C08EE48C135993E2A7840E" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_FDE5172D42A5E65117A85993E2A76693" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_US" xlink:label="loc_country_US_CE35F6DFA801D5BA002A5993E2A8C958" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_FDE5172D42A5E65117A85993E2A76693" xlink:to="loc_country_US_CE35F6DFA801D5BA002A5993E2A8C958" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignPlanMember" xlink:label="loc_us-gaap_ForeignPlanMember_261DCB7AA1A3D8FDF8375993E2A828BB" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_FDE5172D42A5E65117A85993E2A76693" xlink:to="loc_us-gaap_ForeignPlanMember_261DCB7AA1A3D8FDF8375993E2A828BB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_2B71ACA67AA7746187465993E2ADCB49" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_2FE7A9E41823CB55301B5993E2A74972" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_2B71ACA67AA7746187465993E2ADCB49" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_4D27045FBD083EB0831F5993E2AD099B_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_2B71ACA67AA7746187465993E2ADCB49" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_4D27045FBD083EB0831F5993E2AD099B_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_4D27045FBD083EB0831F5993E2AD099B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_2B71ACA67AA7746187465993E2ADCB49" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_4D27045FBD083EB0831F5993E2AD099B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_B5B8B289E34DD2B64AA15993E2AE5FC9" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_4D27045FBD083EB0831F5993E2AD099B" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_B5B8B289E34DD2B64AA15993E2AE5FC9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_D8EF84B1F6385E8E27235993E2AEE267" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligation" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_DBB997DAF1D579E476E55993E2AE8685" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligation_DBB997DAF1D579E476E55993E2AE8685" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_D63CE15BDA17CF57546F5993E2AF6CB5" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_D63CE15BDA17CF57546F5993E2AF6CB5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_2CE28BA9F005A4B54F1A5993E2AFED2C" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_2CE28BA9F005A4B54F1A5993E2AFED2C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant_0C24F847A76FB8E199C15993E2AF9C84" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant_0C24F847A76FB8E199C15993E2AF9C84" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAmendments" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAmendments_64F9C64B32FE0E4E42EB5993E2AF1927" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAmendments_64F9C64B32FE0E4E42EB5993E2AF1927" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_2183BD7471C25DB694035993E2AF5908" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:to="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_2183BD7471C25DB694035993E2AF5908" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanSettlementsAndCurtailmentsBenefitObligation" xlink:label="loc_hsc_DefinedBenefitPlanSettlementsAndCurtailmentsBenefitObligation_C0DC597F965AE597C8625993E2B045C2" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:to="loc_hsc_DefinedBenefitPlanSettlementsAndCurtailmentsBenefitObligation_C0DC597F965AE597C8625993E2B045C2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_130611475E2FF2DDB7865993E2B0F8C5" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_130611475E2FF2DDB7865993E2B0F8C5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation" xlink:label="loc_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation_7DF96C7494D9109052FC5993E2B07614" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:to="loc_us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation_7DF96C7494D9109052FC5993E2B07614" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ChangeinbenefitobligationAcquisition" xlink:label="loc_hsc_ChangeinbenefitobligationAcquisition_F33CD527A15C597D152E5993E2B0C498" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:to="loc_hsc_ChangeinbenefitobligationAcquisition_F33CD527A15C597D152E5993E2B0C498" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ChangeinbenefitobligationInfrastructuretransaction" xlink:label="loc_hsc_ChangeinbenefitobligationInfrastructuretransaction_16702F6FAECA1920F34E5993E2B097A0" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_74F26DBCC769F29A418D5993E2AEE207" xlink:to="loc_hsc_ChangeinbenefitobligationInfrastructuretransaction_16702F6FAECA1920F34E5993E2B097A0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_6D84B78E23CF1B23773D5993E2B1C2D9" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_D8EF84B1F6385E8E27235993E2AEE267" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_6D84B78E23CF1B23773D5993E2B1C2D9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_8C777D9FC03D0201C4265993E2B116C8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_6D84B78E23CF1B23773D5993E2B1C2D9" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_8C777D9FC03D0201C4265993E2B116C8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_4D991A0994876B73D5225993E2B1D6C4" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_6D84B78E23CF1B23773D5993E2B1C2D9" xlink:to="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_4D991A0994876B73D5225993E2B1D6C4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_889DA9A104A7DFB1A28D5993E2B1FC5A" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_6D84B78E23CF1B23773D5993E2B1C2D9" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_889DA9A104A7DFB1A28D5993E2B1FC5A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant_BC147C40977252AFE9575993E2B12841" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_6D84B78E23CF1B23773D5993E2B1C2D9" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant_BC147C40977252AFE9575993E2B12841" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanSettlementsAndCurtailmentsPlanAssets" xlink:label="loc_hsc_DefinedBenefitPlanSettlementsAndCurtailmentsPlanAssets_06048D7709568D0E8FA25993E2B2F10D" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_6D84B78E23CF1B23773D5993E2B1C2D9" xlink:to="loc_hsc_DefinedBenefitPlanSettlementsAndCurtailmentsPlanAssets_06048D7709568D0E8FA25993E2B2F10D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_4F97B0A527969A0623A05993E2B2BBE9" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_6D84B78E23CF1B23773D5993E2B1C2D9" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_4F97B0A527969A0623A05993E2B2BBE9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss_C3E248CE2FF3313E65425993E2B222A3" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_6D84B78E23CF1B23773D5993E2B1C2D9" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsForeignCurrencyTranslationGainLoss_C3E248CE2FF3313E65425993E2B222A3" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanPlanAssetsOther" xlink:label="loc_hsc_DefinedBenefitPlanPlanAssetsOther_1D41DFBF240C9F1409455993E2B21A03" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_6D84B78E23CF1B23773D5993E2B1C2D9" xlink:to="loc_hsc_DefinedBenefitPlanPlanAssetsOther_1D41DFBF240C9F1409455993E2B21A03" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:label="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_6F3A348B6D97764F118A5993E2B2C9D5" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_6D84B78E23CF1B23773D5993E2B1C2D9" xlink:to="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_6F3A348B6D97764F118A5993E2B2C9D5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_BD0BE6AF1BD97F0D02F05993E2B39B81" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_D8EF84B1F6385E8E27235993E2AEE267" xlink:to="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_BD0BE6AF1BD97F0D02F05993E2B39B81" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" xlink:label="loc_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_9A5577FF90323D8960985993E2B3F8F0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_BD0BE6AF1BD97F0D02F05993E2B39B81" xlink:to="loc_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_9A5577FF90323D8960985993E2B3F8F0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_CDF01578AF56C70710345993E2B30F77" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_BD0BE6AF1BD97F0D02F05993E2B39B81" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_CDF01578AF56C70710345993E2B30F77" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_D0AD2E7F936127E54CF05993E2B344D0" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_BD0BE6AF1BD97F0D02F05993E2B39B81" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_D0AD2E7F936127E54CF05993E2B344D0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent" xlink:label="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent_84CE9F3E9C243BF4C6545993E2B38350" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_BD0BE6AF1BD97F0D02F05993E2B39B81" xlink:to="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent_84CE9F3E9C243BF4C6545993E2B38350" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax_23972F9D9432547D74DC5993E2B4D6ED" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_BD0BE6AF1BD97F0D02F05993E2B39B81" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax_23972F9D9432547D74DC5993E2B4D6ED" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract_16772DCC0556B47156015993E2B4EC23" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_D8EF84B1F6385E8E27235993E2AEE267" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract_16772DCC0556B47156015993E2B4EC23" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_74F5E1F938E4F61CE9B05993E2B4350F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract_16772DCC0556B47156015993E2B4EC23" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_74F5E1F938E4F61CE9B05993E2B4350F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax_B502D67A50800D9E740B5993E2B43C52" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract_16772DCC0556B47156015993E2B4EC23" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax_B502D67A50800D9E740B5993E2B43C52" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYearAbstract" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYearAbstract_9CEEA4502EDB5291C2955993E2B59ED4" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_D8EF84B1F6385E8E27235993E2AEE267" xlink:to="loc_us-gaap_DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYearAbstract_9CEEA4502EDB5291C2955993E2B59ED4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear_EED2B1FA5777EB6F73AD5993E2B53AB0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYearAbstract_9CEEA4502EDB5291C2955993E2B59ED4" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedAmortizationOfGainLossNextFiscalYear_EED2B1FA5777EB6F73AD5993E2B53AB0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear_BF90A253B2B7D8AE3F705993E2B59A7F" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYearAbstract_9CEEA4502EDB5291C2955993E2B59ED4" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear_BF90A253B2B7D8AE3F705993E2B59A7F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedAmortizationNextFiscalYear" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedAmortizationNextFiscalYear_5E488B8C27F871170B3E5993E2B597D4" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYearAbstract_9CEEA4502EDB5291C2955993E2B59ED4" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedAmortizationNextFiscalYear_5E488B8C27F871170B3E5993E2B597D4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_D679786A6301C1C9C42B5993E2B54806" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsThatWillBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossInNextFiscalYearAbstract_9CEEA4502EDB5291C2955993E2B59ED4" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_D679786A6301C1C9C42B5993E2B54806" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract" xlink:label="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_42148B02C260A62A843C5993E2B64B15" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_D8EF84B1F6385E8E27235993E2AEE267" xlink:to="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_42148B02C260A62A843C5993E2B64B15" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_0522D85A9E78C01E8E7F5993E2B644FF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_42148B02C260A62A843C5993E2B64B15" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_0522D85A9E78C01E8E7F5993E2B644FF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_8B273D51D79022D5F27B5993E2B64245" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_42148B02C260A62A843C5993E2B64B15" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_8B273D51D79022D5F27B5993E2B64245" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_7A9D67F6B41CF562F1225993E2B6E208" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_42148B02C260A62A843C5993E2B64B15" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_7A9D67F6B41CF562F1225993E2B6E208" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_2B14627520D8CF59B1485993E2B60751" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_42148B02C260A62A843C5993E2B64B15" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_2B14627520D8CF59B1485993E2B60751" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_42962B4A433F3FFD630A5993E2B60CFE" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_42148B02C260A62A843C5993E2B64B15" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_42962B4A433F3FFD630A5993E2B60CFE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_BC400D1DC8E28CA20D975993E2B7DCB4" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanEstimatedFutureBenefitPaymentsAbstract_42148B02C260A62A843C5993E2B64B15" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_BC400D1DC8E28CA20D975993E2B7DCB4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_8AE8CF76C0FA93D2AEF35993E2B79A88" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_D8EF84B1F6385E8E27235993E2AEE267" xlink:to="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_8AE8CF76C0FA93D2AEF35993E2B79A88" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_1D64423968EC1CDF1BB75993E2BC8915" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_8AE8CF76C0FA93D2AEF35993E2B79A88" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_1D64423968EC1CDF1BB75993E2BC8915" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_6F72AD31CA51C7E428B65993E2BD5197" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_8AE8CF76C0FA93D2AEF35993E2B79A88" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_6F72AD31CA51C7E428B65993E2BD5197" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssetsForNextFiscalYear" xlink:label="loc_hsc_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssetsForNextFiscalYear_6C54BC6EB7AD3926F09E5993E2BD4970" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_8AE8CF76C0FA93D2AEF35993E2B79A88" xlink:to="loc_hsc_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssetsForNextFiscalYear_6C54BC6EB7AD3926F09E5993E2BD4970" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_9BE77EA6B9D14958E0B75993E2BD33DC" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_D8EF84B1F6385E8E27235993E2AEE267" xlink:to="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_9BE77EA6B9D14958E0B75993E2BD33DC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_9E79806CC9EAF8921F6F5993E2BEA3CB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_9BE77EA6B9D14958E0B75993E2BD33DC" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_9E79806CC9EAF8921F6F5993E2BEA3CB" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanAssumptionsUsedInCalculatingBenefitObligationDiscountRatePercentOfHighestYieldAaCorporateBondsExcluded" xlink:label="loc_hsc_DefinedBenefitPlanAssumptionsUsedInCalculatingBenefitObligationDiscountRatePercentOfHighestYieldAaCorporateBondsExcluded_2D2946BA20C4901D72905993E2BE2C79" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_9BE77EA6B9D14958E0B75993E2BD33DC" xlink:to="loc_hsc_DefinedBenefitPlanAssumptionsUsedInCalculatingBenefitObligationDiscountRatePercentOfHighestYieldAaCorporateBondsExcluded_2D2946BA20C4901D72905993E2BE2C79" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanAssumptionsUsedInCalculatingBenefitObligationDiscountRatePercentOfLowestYieldAaCorporateBondsExcluded" xlink:label="loc_hsc_DefinedBenefitPlanAssumptionsUsedInCalculatingBenefitObligationDiscountRatePercentOfLowestYieldAaCorporateBondsExcluded_8D927BA0450892CDD68E5993E2BEBA3A" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_9BE77EA6B9D14958E0B75993E2BD33DC" xlink:to="loc_hsc_DefinedBenefitPlanAssumptionsUsedInCalculatingBenefitObligationDiscountRatePercentOfLowestYieldAaCorporateBondsExcluded_8D927BA0450892CDD68E5993E2BEBA3A" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/EmployeeBenefitPlansDetails3" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_609000BA1349C77337B662FA5BAB2913" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_609000BA1349C77337B662FA5BAB2913" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationAxis" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationAxis_18B5BA83CFC333AA462A62FA5BAB9CB7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_609000BA1349C77337B662FA5BAB2913" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationAxis_18B5BA83CFC333AA462A62FA5BAB9CB7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationDomain" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_CAC753B8D266F50A462362FA5BAB1064_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_18B5BA83CFC333AA462A62FA5BAB9CB7" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_CAC753B8D266F50A462362FA5BAB1064_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationDomain" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_CAC753B8D266F50A462362FA5BAB1064" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_18B5BA83CFC333AA462A62FA5BAB9CB7" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_CAC753B8D266F50A462362FA5BAB1064" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_InternationalOtherThanUnitedKingdomMember" xlink:label="loc_hsc_InternationalOtherThanUnitedKingdomMember_B7373A10B7663498D93F630DD99FC70D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_CAC753B8D266F50A462362FA5BAB1064" xlink:to="loc_hsc_InternationalOtherThanUnitedKingdomMember_B7373A10B7663498D93F630DD99FC70D" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_US" xlink:label="loc_country_US_64DACCECF39A72554E0C62FA5BAB54BE" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_CAC753B8D266F50A462362FA5BAB1064" xlink:to="loc_country_US_64DACCECF39A72554E0C62FA5BAB54BE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignPlanMember" xlink:label="loc_us-gaap_ForeignPlanMember_59A79C2D232216B9A57362FA5BAFA2E4" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_CAC753B8D266F50A462362FA5BAB1064" xlink:to="loc_us-gaap_ForeignPlanMember_59A79C2D232216B9A57362FA5BAFA2E4" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_GB" xlink:label="loc_country_GB_A92B6F9A2A2B495153FA630CD0F87EFB" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_CAC753B8D266F50A462362FA5BAB1064" xlink:to="loc_country_GB_A92B6F9A2A2B495153FA630CD0F87EFB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_55F5311704116AF483E062FA5BAFCAA9" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_609000BA1349C77337B662FA5BAB2913" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_55F5311704116AF483E062FA5BAFCAA9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_F73356A8B2CD9EB75AC862FA5BAF4980_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_55F5311704116AF483E062FA5BAFCAA9" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_F73356A8B2CD9EB75AC862FA5BAF4980_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_F73356A8B2CD9EB75AC862FA5BAF4980" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_55F5311704116AF483E062FA5BAFCAA9" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_F73356A8B2CD9EB75AC862FA5BAF4980" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_F4FBDBF6E540C2E52F2862FA5BAFE0DA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_F73356A8B2CD9EB75AC862FA5BAF4980" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_F4FBDBF6E540C2E52F2862FA5BAFE0DA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87A3FA06DF407A9F6D6762FA5BAFD13F" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_609000BA1349C77337B662FA5BAB2913" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87A3FA06DF407A9F6D6762FA5BAFD13F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_43AAF2D0A0AA9BB4D12F62FA5BAF3B0B_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87A3FA06DF407A9F6D6762FA5BAFD13F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_43AAF2D0A0AA9BB4D12F62FA5BAF3B0B_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_43AAF2D0A0AA9BB4D12F62FA5BAF3B0B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_87A3FA06DF407A9F6D6762FA5BAFD13F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_43AAF2D0A0AA9BB4D12F62FA5BAF3B0B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_294C650C45B7CBE82DEC62FA5BAF2590" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_43AAF2D0A0AA9BB4D12F62FA5BAF3B0B" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_294C650C45B7CBE82DEC62FA5BAF2590" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember" xlink:label="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_A255ACCC85EB8FBEF2D262FA5BAFCE50" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_43AAF2D0A0AA9BB4D12F62FA5BAF3B0B" xlink:to="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_A255ACCC85EB8FBEF2D262FA5BAFCE50" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_FBB9326BA6748D774B7962FA5BAF9D62" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_43AAF2D0A0AA9BB4D12F62FA5BAF3B0B" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_FBB9326BA6748D774B7962FA5BAF9D62" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_6C612ED995D41C0B807162FA5BAF6AEE" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_609000BA1349C77337B662FA5BAB2913" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_6C612ED995D41C0B807162FA5BAF6AEE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanAssetCategoriesDomain" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_6C612ED995D41C0B807162FA5BAF6AEE" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanAssetCategoriesDomain" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_6C612ED995D41C0B807162FA5BAF6AEE" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquitySecuritiesMember" xlink:label="loc_us-gaap_EquitySecuritiesMember_0DC5880E80D83862209E62FA5BAF45BA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:to="loc_us-gaap_EquitySecuritiesMember_0DC5880E80D83862209E62FA5BAF45BA" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_EquitySecuritiesDomesticMember" xlink:label="loc_hsc_EquitySecuritiesDomesticMember_5CC14E2377EC864CED6D62FA5BAF5213" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:to="loc_hsc_EquitySecuritiesDomesticMember_5CC14E2377EC864CED6D62FA5BAF5213" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_EquityFundsDomesticMember" xlink:label="loc_hsc_EquityFundsDomesticMember_503D7CE8B7776A95ACB162FA5BAF1C97" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:to="loc_hsc_EquityFundsDomesticMember_503D7CE8B7776A95ACB162FA5BAF1C97" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_EquitySecuritiesInternationalMember" xlink:label="loc_hsc_EquitySecuritiesInternationalMember_13D9C94A8067888F00B362FA5BAF3728" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:to="loc_hsc_EquitySecuritiesInternationalMember_13D9C94A8067888F00B362FA5BAF3728" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_EquityFundsInternationalMember" xlink:label="loc_hsc_EquityFundsInternationalMember_DA95F081C79D7FD0E62162FA5BB3448E" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:to="loc_hsc_EquityFundsInternationalMember_DA95F081C79D7FD0E62162FA5BB3448E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CompanysOwnCommonStockMember" xlink:label="loc_hsc_CompanysOwnCommonStockMember_4E8E93098C395D5F833662FA5BB33D12" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:to="loc_hsc_CompanysOwnCommonStockMember_4E8E93098C395D5F833662FA5BB33D12" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityFundsMember" xlink:label="loc_us-gaap_EquityFundsMember_F9145B3EB502EA45B97E62FA5BB3EDBD" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:to="loc_us-gaap_EquityFundsMember_F9145B3EB502EA45B97E62FA5BB3EDBD" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtSecuritiesMember" xlink:label="loc_us-gaap_DebtSecuritiesMember_F718C90B952D107E14F162FA5BB3375F" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:to="loc_us-gaap_DebtSecuritiesMember_F718C90B952D107E14F162FA5BB3375F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FixedIncomeFundsMember" xlink:label="loc_us-gaap_FixedIncomeFundsMember_63E879A65443039228D362FA5BB327D1" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesMember_F718C90B952D107E14F162FA5BB3375F" xlink:to="loc_us-gaap_FixedIncomeFundsMember_63E879A65443039228D362FA5BB327D1" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_InsuranceContractMember" xlink:label="loc_hsc_InsuranceContractMember_C206BFC6AEC102E74A6C62FA5BB84894" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesMember_F718C90B952D107E14F162FA5BB3375F" xlink:to="loc_hsc_InsuranceContractMember_C206BFC6AEC102E74A6C62FA5BB84894" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_OtherAssetCategoryMember" xlink:label="loc_hsc_OtherAssetCategoryMember_525244EEC9AEED6E567C62FA5BB8DD46" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:to="loc_hsc_OtherAssetCategoryMember_525244EEC9AEED6E567C62FA5BB8DD46" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_OtherAssetCategoriesMutualFundsMember" xlink:label="loc_hsc_OtherAssetCategoriesMutualFundsMember_797D5A70760187CC966D62FA5BB8AAB0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_OtherAssetCategoryMember_525244EEC9AEED6E567C62FA5BB8DD46" xlink:to="loc_hsc_OtherAssetCategoriesMutualFundsMember_797D5A70760187CC966D62FA5BB8AAB0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsMember" xlink:label="loc_us-gaap_CashAndCashEquivalentsMember_BFFF0BDADC2FD13C14CE62FA5BB83C44" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:to="loc_us-gaap_CashAndCashEquivalentsMember_BFFF0BDADC2FD13C14CE62FA5BB83C44" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PartnershipMember" xlink:label="loc_us-gaap_PartnershipMember_F9B536B86B753825AD5D62FA5BB8C7CE" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_A8977D7B1A1AAF69544562FA5BAF283A" xlink:to="loc_us-gaap_PartnershipMember_F9B536B86B753825AD5D62FA5BB8C7CE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_ACA4BCF86F045E45C77A62FA5BB8DB24" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_609000BA1349C77337B662FA5BAB2913" xlink:to="loc_srt_RangeAxis_ACA4BCF86F045E45C77A62FA5BB8DB24" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_38AA7E3111EE9882A67B62FA5BB88B54_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_ACA4BCF86F045E45C77A62FA5BB8DB24" xlink:to="loc_srt_RangeMember_38AA7E3111EE9882A67B62FA5BB88B54_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_38AA7E3111EE9882A67B62FA5BB88B54" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_ACA4BCF86F045E45C77A62FA5BB8DB24" xlink:to="loc_srt_RangeMember_38AA7E3111EE9882A67B62FA5BB88B54" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_4D87E44D2ED328D03AC062FA5BB81370" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_38AA7E3111EE9882A67B62FA5BB88B54" xlink:to="loc_srt_MinimumMember_4D87E44D2ED328D03AC062FA5BB81370" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_EAB9FD6C466490D7955462FA5BBC4350" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_38AA7E3111EE9882A67B62FA5BB88B54" xlink:to="loc_srt_MaximumMember_EAB9FD6C466490D7955462FA5BBC4350" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation_781604D3490E9010891862FA5BBCECDC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation_781604D3490E9010891862FA5BBCECDC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract_C43A333185EA15D16AA262FA5BBC1563" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract_C43A333185EA15D16AA262FA5BBC1563" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation_7A9F4E8536B1B3AA899762FA5BBC2558" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract_C43A333185EA15D16AA262FA5BBC1563" xlink:to="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation_7A9F4E8536B1B3AA899762FA5BBC2558" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation_BB3C3BA7639065B1495862FA5BBC6215" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract_C43A333185EA15D16AA262FA5BBC1563" xlink:to="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation_BB3C3BA7639065B1495862FA5BBC6215" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets_4491B59E5E7F56AB418262FA5BBDBA49" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract_C43A333185EA15D16AA262FA5BBC1563" xlink:to="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets_4491B59E5E7F56AB418262FA5BBDBA49" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanInformationAboutPlanAssetsAbstract" xlink:label="loc_us-gaap_DefinedBenefitPlanInformationAboutPlanAssetsAbstract_16C8C36EFF4BE655724762FA5BBD7A90" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAbstract_C43A333185EA15D16AA262FA5BBC1563" xlink:to="loc_us-gaap_DefinedBenefitPlanInformationAboutPlanAssetsAbstract_16C8C36EFF4BE655724762FA5BBD7A90" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations_A082E787713C96AC628762FA5BBD39C8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanInformationAboutPlanAssetsAbstract_16C8C36EFF4BE655724762FA5BBD7A90" xlink:to="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations_A082E787713C96AC628762FA5BBD39C8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAssetsTargetAllocationsAbstract" xlink:label="loc_us-gaap_DefinedBenefitPlanAssetsTargetAllocationsAbstract_1C94CA38CD5A52743ECA62FA5BBD11F3" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanInformationAboutPlanAssetsAbstract_16C8C36EFF4BE655724762FA5BBD7A90" xlink:to="loc_us-gaap_DefinedBenefitPlanAssetsTargetAllocationsAbstract_1C94CA38CD5A52743ECA62FA5BBD11F3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_C5E4DF177BAA4DE7F01D62FA5BBDB487" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAssetsTargetAllocationsAbstract_1C94CA38CD5A52743ECA62FA5BBD11F3" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_C5E4DF177BAA4DE7F01D62FA5BBDB487" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanExpectedLongTermReturnOnPlanAssetsNumberOfCapitalMarketResultsSimulated" xlink:label="loc_hsc_DefinedBenefitPlanExpectedLongTermReturnOnPlanAssetsNumberOfCapitalMarketResultsSimulated_7029CA440ADC0F2CF3DD62FA5BBDB69C" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_hsc_DefinedBenefitPlanExpectedLongTermReturnOnPlanAssetsNumberOfCapitalMarketResultsSimulated_7029CA440ADC0F2CF3DD62FA5BBDB69C" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanExpectedLongTermReturnOnPlanAssetsPeriodForWhichResultsOfCapitalMarketsSimulated" xlink:label="loc_hsc_DefinedBenefitPlanExpectedLongTermReturnOnPlanAssetsPeriodForWhichResultsOfCapitalMarketsSimulated_3F6766CF605F0A2ED74262FA5BBD3B4A" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_hsc_DefinedBenefitPlanExpectedLongTermReturnOnPlanAssetsPeriodForWhichResultsOfCapitalMarketsSimulated_3F6766CF605F0A2ED74262FA5BBD3B4A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssetsForNextFiscalYear" xlink:label="loc_hsc_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssetsForNextFiscalYear_506CA7F3352343326D2E62FA5BBF832C" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_hsc_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssetsForNextFiscalYear_506CA7F3352343326D2E62FA5BBF832C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_D2BA372EB89347BACF0C62FA5BBFF6CE" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_D2BA372EB89347BACF0C62FA5BBFF6CE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanNumberOfSharesOfEquitySecuritiesIssuedByEmployerAndRelatedPartiesIncludedInPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanNumberOfSharesOfEquitySecuritiesIssuedByEmployerAndRelatedPartiesIncludedInPlanAssets_D536178930B102C2777162FA5BBFE22C" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_us-gaap_DefinedBenefitPlanNumberOfSharesOfEquitySecuritiesIssuedByEmployerAndRelatedPartiesIncludedInPlanAssets_D536178930B102C2777162FA5BBFE22C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAmountOfEmployerAndRelatedPartySecuritiesIncludedInPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountOfEmployerAndRelatedPartySecuritiesIncludedInPlanAssets_87E9DFDDFD5154A6789762FA5BBFF85F" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_us-gaap_DefinedBenefitPlanAmountOfEmployerAndRelatedPartySecuritiesIncludedInPlanAssets_87E9DFDDFD5154A6789762FA5BBFF85F" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DefinedBenefitPlanAssetsAsPercentageOfForeignPlanAssets" xlink:label="loc_hsc_DefinedBenefitPlanAssetsAsPercentageOfForeignPlanAssets_B668A0E18691599B485C62FA5BBFA44B" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_hsc_DefinedBenefitPlanAssetsAsPercentageOfForeignPlanAssets_B668A0E18691599B485C62FA5BBFA44B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_DB563CC3733098A1BF9562FA5BBF7331" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_DB563CC3733098A1BF9562FA5BBF7331" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_C3E75898891AE144351C62FA5BBF18FC" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_038DEDF088E216A352FD62FA5BBCEED9" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_C3E75898891AE144351C62FA5BBF18FC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_D3E42E1CE15B1735068862FA5BBF5ABB" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_C3E75898891AE144351C62FA5BBF18FC" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_D3E42E1CE15B1735068862FA5BBF5ABB" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/EmployeeBenefitPlansDetails4" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/EmployeeBenefitPlansTables" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_583650F954ED98F6431841E02103BA96" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_583650F954ED98F6431841E02103BA96" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationAxis" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationAxis_F4D28D54DC864052590841E0210396F5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_583650F954ED98F6431841E02103BA96" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationAxis_F4D28D54DC864052590841E0210396F5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationDomain" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_5AE03DC5616CFB82B1F241E021035292_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_F4D28D54DC864052590841E0210396F5" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_5AE03DC5616CFB82B1F241E021035292_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanSponsorLocationDomain" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_5AE03DC5616CFB82B1F241E021035292" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_F4D28D54DC864052590841E0210396F5" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_5AE03DC5616CFB82B1F241E021035292" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_US" xlink:label="loc_country_US_D960F1925B76656E8EE041E02103628A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_5AE03DC5616CFB82B1F241E021035292" xlink:to="loc_country_US_D960F1925B76656E8EE041E02103628A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignPlanMember" xlink:label="loc_us-gaap_ForeignPlanMember_6B3690FBCFC8335D0BB341E02103BB99" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_5AE03DC5616CFB82B1F241E021035292" xlink:to="loc_us-gaap_ForeignPlanMember_6B3690FBCFC8335D0BB341E02103BB99" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_05474C73A14592EA17E941E0210340CD" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_583650F954ED98F6431841E02103BA96" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_05474C73A14592EA17E941E0210340CD" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_36F699DE700DBCFA9E1841E02103642B_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_05474C73A14592EA17E941E0210340CD" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_36F699DE700DBCFA9E1841E02103642B_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_36F699DE700DBCFA9E1841E02103642B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_05474C73A14592EA17E941E0210340CD" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_36F699DE700DBCFA9E1841E02103642B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_DF9A01001B2968ECC76741E021034E48" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_36F699DE700DBCFA9E1841E02103642B" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_DF9A01001B2968ECC76741E021034E48" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfNetBenefitCostsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfNetBenefitCostsTableTextBlock_0E4A3FA00782E89BCAE741E021039442" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:to="loc_us-gaap_ScheduleOfNetBenefitCostsTableTextBlock_0E4A3FA00782E89BCAE741E021039442" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfNetFundedStatusTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfNetFundedStatusTableTextBlock_46ADC7D6B6C389B9E72441E021036E55" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:to="loc_us-gaap_ScheduleOfNetFundedStatusTableTextBlock_46ADC7D6B6C389B9E72441E021036E55" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock_BB88F61C730939FE506841E0210361A7" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:to="loc_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock_BB88F61C730939FE506841E0210361A7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock_9AE0AD9649DFC8E0149641E021030409" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:to="loc_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock_9AE0AD9649DFC8E0149641E021030409" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAmountsInAccumulatedOtherComprehensiveIncomeLossToBeRecognizedOverNextFiscalYearTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfAmountsInAccumulatedOtherComprehensiveIncomeLossToBeRecognizedOverNextFiscalYearTableTextBlock_D7BB8F4EA74AEB9A200341E02103DE23" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:to="loc_us-gaap_ScheduleOfAmountsInAccumulatedOtherComprehensiveIncomeLossToBeRecognizedOverNextFiscalYearTableTextBlock_D7BB8F4EA74AEB9A200341E02103DE23" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_D237D2DCCA141AD3C65841E021039682" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:to="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_D237D2DCCA141AD3C65841E021039682" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock_B532CD92A1171A68B66841E0210348EB" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:to="loc_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock_B532CD92A1171A68B66841E0210348EB" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ScheduleOfAccumulatedBenefitObligationsTableTextBlock" xlink:label="loc_hsc_ScheduleOfAccumulatedBenefitObligationsTableTextBlock_D4C4D07802C3D33359F741E0210308EA" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:to="loc_hsc_ScheduleOfAccumulatedBenefitObligationsTableTextBlock_D4C4D07802C3D33359F741E0210308EA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAccumulatedBenefitObligationsInExcessOfFairValueOfPlanAssetsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfAccumulatedBenefitObligationsInExcessOfFairValueOfPlanAssetsTableTextBlock_38CD11E112A11022944B41E021038E15" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:to="loc_us-gaap_ScheduleOfAccumulatedBenefitObligationsInExcessOfFairValueOfPlanAssetsTableTextBlock_38CD11E112A11022944B41E021038E15" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock_272129CFFADAA49BA72A41E021032D30" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ABAB24EAC7CA87F79C7E41E02103622C" xlink:to="loc_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock_272129CFFADAA49BA72A41E021032D30" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/FinancialInstruments" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/FinancialInstrumentsEffectOfDerivativeInstrumentsOnConsolidatedStatementsOfOperationsAndConsolidatedStatementsOfComprehensiveIncomeLossDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_862A391208E83114CD885F8AE7DD8DF8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_862A391208E83114CD885F8AE7DD8DF8" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis_EEBC16C89284F0031C895F8AE7DDE2F3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_862A391208E83114CD885F8AE7DD8DF8" xlink:to="loc_srt_ProductOrServiceAxis_EEBC16C89284F0031C895F8AE7DDE2F3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_BA1AEA596542A27F94F45F8AE7DD21DE_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_EEBC16C89284F0031C895F8AE7DDE2F3" xlink:to="loc_srt_ProductsAndServicesDomain_BA1AEA596542A27F94F45F8AE7DD21DE_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_BA1AEA596542A27F94F45F8AE7DD21DE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_EEBC16C89284F0031C895F8AE7DDE2F3" xlink:to="loc_srt_ProductsAndServicesDomain_BA1AEA596542A27F94F45F8AE7DD21DE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProductMember" xlink:label="loc_us-gaap_ProductMember_C639345BEE11CDFE74075F8AE7DD3ECD" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_BA1AEA596542A27F94F45F8AE7DD21DE" xlink:to="loc_us-gaap_ProductMember_C639345BEE11CDFE74075F8AE7DD3ECD" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ProductsAndServicesServiceRevenueMember" xlink:label="loc_hsc_ProductsAndServicesServiceRevenueMember_F4E3D937A01F895F641D5F8AE7DD0E73" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_BA1AEA596542A27F94F45F8AE7DD21DE" xlink:to="loc_hsc_ProductsAndServicesServiceRevenueMember_F4E3D937A01F895F641D5F8AE7DD0E73" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_D6B19508972D231BEEDD5F8AE7DDFD2B" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_862A391208E83114CD885F8AE7DD8DF8" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_D6B19508972D231BEEDD5F8AE7DDFD2B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_1F30A3F265D1096F6E885F8AE7DDC4AB_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_D6B19508972D231BEEDD5F8AE7DDFD2B" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_1F30A3F265D1096F6E885F8AE7DDC4AB_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_1F30A3F265D1096F6E885F8AE7DDC4AB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_D6B19508972D231BEEDD5F8AE7DDFD2B" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_1F30A3F265D1096F6E885F8AE7DDC4AB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignExchangeForwardMember" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_D441CEBC1CBB7C5E4AD25F8AE7E032FF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_1F30A3F265D1096F6E885F8AE7DDC4AB" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_D441CEBC1CBB7C5E4AD25F8AE7E032FF" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ForeignExchangeForwardTwoMember" xlink:label="loc_hsc_ForeignExchangeForwardTwoMember_BAC746148700783C14C45F8AE7E058D0" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_1F30A3F265D1096F6E885F8AE7DDC4AB" xlink:to="loc_hsc_ForeignExchangeForwardTwoMember_BAC746148700783C14C45F8AE7E058D0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="loc_us-gaap_InterestRateSwapMember_02D22D65D44FE6DF8C815F8AE7E07D10" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_1F30A3F265D1096F6E885F8AE7DDC4AB" xlink:to="loc_us-gaap_InterestRateSwapMember_02D22D65D44FE6DF8C815F8AE7E07D10" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_InterestRateSwapTwoMember" xlink:label="loc_hsc_InterestRateSwapTwoMember_AC4C065E7ED51AF480985F8AE7E0DFEC" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_1F30A3F265D1096F6E885F8AE7DDC4AB" xlink:to="loc_hsc_InterestRateSwapTwoMember_AC4C065E7ED51AF480985F8AE7E0DFEC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CrossCurrencyInterestRateContractMember" xlink:label="loc_us-gaap_CrossCurrencyInterestRateContractMember_E2DBF0CEE95A80D5C88E5F8AE7E0D526" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_1F30A3F265D1096F6E885F8AE7DDC4AB" xlink:to="loc_us-gaap_CrossCurrencyInterestRateContractMember_E2DBF0CEE95A80D5C88E5F8AE7E0D526" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignExchangeContractMember" xlink:label="loc_us-gaap_ForeignExchangeContractMember_277542C8EBF52E6737E95F8AE7E00446" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_1F30A3F265D1096F6E885F8AE7DDC4AB" xlink:to="loc_us-gaap_ForeignExchangeContractMember_277542C8EBF52E6737E95F8AE7E00446" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_E3A9B59B2586641AC3175F8AE7E6CD83" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_862A391208E83114CD885F8AE7DD8DF8" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_E3A9B59B2586641AC3175F8AE7E6CD83" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_E99E545EFE85B031681C5F8AE7E64C25_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_E3A9B59B2586641AC3175F8AE7E6CD83" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_E99E545EFE85B031681C5F8AE7E64C25_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_E99E545EFE85B031681C5F8AE7E64C25" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_E3A9B59B2586641AC3175F8AE7E6CD83" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_E99E545EFE85B031681C5F8AE7E64C25" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SalesMember" xlink:label="loc_us-gaap_SalesMember_DC42C2DF67F2AAC849B45F8AE7E6E4ED" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_E99E545EFE85B031681C5F8AE7E64C25" xlink:to="loc_us-gaap_SalesMember_DC42C2DF67F2AAC849B45F8AE7E6E4ED" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="loc_us-gaap_CostOfSalesMember_FC38315B3B79C0FDBAFE5F8AE7E66975" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_E99E545EFE85B031681C5F8AE7E64C25" xlink:to="loc_us-gaap_CostOfSalesMember_FC38315B3B79C0FDBAFE5F8AE7E66975" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_A5C0564AC9482308B6BF5F8AE7E653CB" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_E99E545EFE85B031681C5F8AE7E64C25" xlink:to="loc_us-gaap_RetainedEarningsMember_A5C0564AC9482308B6BF5F8AE7E653CB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestExpenseMember" xlink:label="loc_us-gaap_InterestExpenseMember_69E1104335CA0E2AA7775F8AE7E64500" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_E99E545EFE85B031681C5F8AE7E64C25" xlink:to="loc_us-gaap_InterestExpenseMember_69E1104335CA0E2AA7775F8AE7E64500" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfGoodsTotalMember" xlink:label="loc_us-gaap_CostOfGoodsTotalMember_D08C9C666F6541C93E2F5F8AE7E66B54" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_E99E545EFE85B031681C5F8AE7E64C25" xlink:to="loc_us-gaap_CostOfGoodsTotalMember_D08C9C666F6541C93E2F5F8AE7E66B54" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember" xlink:label="loc_hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember_96702C5AC4F9A08780D95F8AE7E66552" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_E99E545EFE85B031681C5F8AE7E64C25" xlink:to="loc_hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember_96702C5AC4F9A08780D95F8AE7E66552" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_436A235C6116B5F3C7ED5F8AE7E6DEA3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_436A235C6116B5F3C7ED5F8AE7E6DEA3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_DAF816E925BA05EF98B55F8AE7E624EE" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_DAF816E925BA05EF98B55F8AE7E624EE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_DA3F6D513CE5F5FB2F775F8AE7E61894" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:to="loc_us-gaap_InterestExpense_DA3F6D513CE5F5FB2F775F8AE7E61894" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_96C3DA9AA9F21DA13D995F8AE7E60F46" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:to="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_96C3DA9AA9F21DA13D995F8AE7E60F46" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_0C6E3AFF93A67A16A7475F8AE7E64D0F" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_0C6E3AFF93A67A16A7475F8AE7E64D0F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet" xlink:label="loc_us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet_755C449912F5320452DD5F8AE7E65604" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:to="loc_us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet_755C449912F5320452DD5F8AE7E65604" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseBeforeAdjustmentsAndTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseBeforeAdjustmentsAndTax_B07D913D620B902CC27A5F8AE7E6F02C" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseBeforeAdjustmentsAndTax_B07D913D620B902CC27A5F8AE7E6F02C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax_D11029F4E2CD07C4E2755F8AE7EA6077" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax_D11029F4E2CD07C4E2755F8AE7EA6077" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet_C73E2B12BC8016BA77E35F8AE7EA0168" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet_C73E2B12BC8016BA77E35F8AE7EA0168" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNetAbstract" xlink:label="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNetAbstract_A0C570D7B1B8664120705F8AE7EAAB49" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_76D94BE16EBCA82E33565F8AE7E617CE" xlink:to="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNetAbstract_A0C570D7B1B8664120705F8AE7EAAB49" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet" xlink:label="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_B249E02195D14EE5FA865F8AE7EACBCE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNetAbstract_A0C570D7B1B8664120705F8AE7EAAB49" xlink:to="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_B249E02195D14EE5FA865F8AE7EACBCE" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/FinancialInstrumentsEffectOfDerivativesDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativesFairValueLineItems" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_443F45F15DDB440B81EA5FAE871EE8E6" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_96E4D8F48638B690AFCD5FAE87195FF1" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_443F45F15DDB440B81EA5FAE871EE8E6" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_96E4D8F48638B690AFCD5FAE87195FF1" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_277098D108C1ED6099FE5FAE8795E383" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_96E4D8F48638B690AFCD5FAE87195FF1" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_277098D108C1ED6099FE5FAE8795E383" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_3487D3610B0371835E665FAE879AA1B6_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_277098D108C1ED6099FE5FAE8795E383" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_3487D3610B0371835E665FAE879AA1B6_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_3487D3610B0371835E665FAE879AA1B6" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_277098D108C1ED6099FE5FAE8795E383" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_3487D3610B0371835E665FAE879AA1B6" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="loc_us-gaap_CostOfSalesMember_42A727803398377DEE9F5FAE87DC2292" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3487D3610B0371835E665FAE879AA1B6" xlink:to="loc_us-gaap_CostOfSalesMember_42A727803398377DEE9F5FAE87DC2292" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_342902B20A21A982BE885FAE8804ECFB" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3487D3610B0371835E665FAE879AA1B6" xlink:to="loc_us-gaap_RetainedEarningsMember_342902B20A21A982BE885FAE8804ECFB" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember" xlink:label="loc_hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember_068EC4A9C50EAAB3E6DA5FAE882CEB35" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3487D3610B0371835E665FAE879AA1B6" xlink:to="loc_hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember_068EC4A9C50EAAB3E6DA5FAE882CEB35" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestExpenseMember" xlink:label="loc_us-gaap_InterestExpenseMember_CE95140AD8288624E02A5FAE8852D2E1" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3487D3610B0371835E665FAE879AA1B6" xlink:to="loc_us-gaap_InterestExpenseMember_CE95140AD8288624E02A5FAE8852D2E1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_7D4A37D11018917FFB235FAE871ADC73" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_96E4D8F48638B690AFCD5FAE87195FF1" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_7D4A37D11018917FFB235FAE871ADC73" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_77D53D02F2366235F7675FAE871AD7B5_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_7D4A37D11018917FFB235FAE871ADC73" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_77D53D02F2366235F7675FAE871AD7B5_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_77D53D02F2366235F7675FAE871AD7B5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_7D4A37D11018917FFB235FAE871ADC73" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_77D53D02F2366235F7675FAE871AD7B5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignExchangeForwardMember" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_8070CC856B5097471C825FAE87C71599" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_77D53D02F2366235F7675FAE871AD7B5" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_8070CC856B5097471C825FAE87C71599" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ForeignExchangeForwardTwoMember" xlink:label="loc_hsc_ForeignExchangeForwardTwoMember_8B6A59F7BB68559291145FAE87F0DABE" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_77D53D02F2366235F7675FAE871AD7B5" xlink:to="loc_hsc_ForeignExchangeForwardTwoMember_8B6A59F7BB68559291145FAE87F0DABE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="loc_us-gaap_InterestRateSwapMember_1B66053FCC84AAEDBA435FAE8816031F" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_77D53D02F2366235F7675FAE871AD7B5" xlink:to="loc_us-gaap_InterestRateSwapMember_1B66053FCC84AAEDBA435FAE8816031F" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_InterestRateSwapTwoMember" xlink:label="loc_hsc_InterestRateSwapTwoMember_B0492DEEEE46A71A44F55FAE8840C05A" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_77D53D02F2366235F7675FAE871AD7B5" xlink:to="loc_hsc_InterestRateSwapTwoMember_B0492DEEEE46A71A44F55FAE8840C05A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CrossCurrencyInterestRateContractMember" xlink:label="loc_us-gaap_CrossCurrencyInterestRateContractMember_609B5FD95A8767C6CAD45FAE886AC198" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_77D53D02F2366235F7675FAE871AD7B5" xlink:to="loc_us-gaap_CrossCurrencyInterestRateContractMember_609B5FD95A8767C6CAD45FAE886AC198" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_707435A3B77A512E01AA5FAE874077B5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_443F45F15DDB440B81EA5FAE871EE8E6" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_707435A3B77A512E01AA5FAE874077B5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax_3774AB374DDAF3693F4C5FAE87510152" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_443F45F15DDB440B81EA5FAE871EE8E6" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax_3774AB374DDAF3693F4C5FAE87510152" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet" xlink:label="loc_us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet_1CF5701726563BDEB0965FAE877AFCDF" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_443F45F15DDB440B81EA5FAE871EE8E6" xlink:to="loc_us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet_1CF5701726563BDEB0965FAE877AFCDF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_3527D1CE35DD85066D565FAE875EED21" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_443F45F15DDB440B81EA5FAE871EE8E6" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_3527D1CE35DD85066D565FAE875EED21" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet_1433E4496AFC21BD4D715FAE87694442" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_443F45F15DDB440B81EA5FAE871EE8E6" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet_1433E4496AFC21BD4D715FAE87694442" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/FinancialInstrumentsFairValueOfOutstandingDerivativeContractsRecordedAsAssetsAndLiabilitiesDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativesFairValueLineItems" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_0BC0883237F14647584A3AA585FA397D" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_CDE71C300E34D267115F3AA585F6C22B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_0BC0883237F14647584A3AA585FA397D" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_CDE71C300E34D267115F3AA585F6C22B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_HedgingDesignationAxis" xlink:label="loc_us-gaap_HedgingDesignationAxis_C084C576ADB56E4739B73AA585F6767D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_CDE71C300E34D267115F3AA585F6C22B" xlink:to="loc_us-gaap_HedgingDesignationAxis_C084C576ADB56E4739B73AA585F6767D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_3C29EEEBC84397A1D5ED3AA585F707A3_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_C084C576ADB56E4739B73AA585F6767D" xlink:to="loc_us-gaap_HedgingDesignationDomain_3C29EEEBC84397A1D5ED3AA585F707A3_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_HedgingDesignationDomain" xlink:label="loc_us-gaap_HedgingDesignationDomain_3C29EEEBC84397A1D5ED3AA585F707A3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_C084C576ADB56E4739B73AA585F6767D" xlink:to="loc_us-gaap_HedgingDesignationDomain_3C29EEEBC84397A1D5ED3AA585F707A3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_33F0E8F683EEAF04455E3AA585F7575D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_3C29EEEBC84397A1D5ED3AA585F707A3" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_33F0E8F683EEAF04455E3AA585F7575D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NondesignatedMember" xlink:label="loc_us-gaap_NondesignatedMember_7AE7F06E4804E97DD5643AA585F738D2" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_3C29EEEBC84397A1D5ED3AA585F707A3" xlink:to="loc_us-gaap_NondesignatedMember_7AE7F06E4804E97DD5643AA585F738D2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_A3EF09DC612156FB14FF3AA585F8C8FB" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_CDE71C300E34D267115F3AA585F6C22B" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_A3EF09DC612156FB14FF3AA585F8C8FB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_0B156B0C9FCB357B1C313AA585F8549D_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_A3EF09DC612156FB14FF3AA585F8C8FB" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_0B156B0C9FCB357B1C313AA585F8549D_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_0B156B0C9FCB357B1C313AA585F8549D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_A3EF09DC612156FB14FF3AA585F8C8FB" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_0B156B0C9FCB357B1C313AA585F8549D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignExchangeForwardMember" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_2CED53937731FB13A0433AA585F88AA1" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_0B156B0C9FCB357B1C313AA585F8549D" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_2CED53937731FB13A0433AA585F88AA1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="loc_us-gaap_InterestRateSwapMember_F072C908925DAB6F17963AA585F86755" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_0B156B0C9FCB357B1C313AA585F8549D" xlink:to="loc_us-gaap_InterestRateSwapMember_F072C908925DAB6F17963AA585F86755" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_225E6D55A3360962EDC23AA585F8C3C0" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_CDE71C300E34D267115F3AA585F6C22B" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_225E6D55A3360962EDC23AA585F8C3C0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_1E3AEFE37459555776783AA585F95F18_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_225E6D55A3360962EDC23AA585F8C3C0" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_1E3AEFE37459555776783AA585F95F18_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_1E3AEFE37459555776783AA585F95F18" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_225E6D55A3360962EDC23AA585F8C3C0" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_1E3AEFE37459555776783AA585F95F18" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherCurrentAssetsMember" xlink:label="loc_us-gaap_OtherCurrentAssetsMember_BB95FCC63429970401153AA585F9683A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_1E3AEFE37459555776783AA585F95F18" xlink:to="loc_us-gaap_OtherCurrentAssetsMember_BB95FCC63429970401153AA585F9683A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherNoncurrentAssetsMember" xlink:label="loc_us-gaap_OtherNoncurrentAssetsMember_48471416FFAEAD6009DB3AA585F98767" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_1E3AEFE37459555776783AA585F95F18" xlink:to="loc_us-gaap_OtherNoncurrentAssetsMember_48471416FFAEAD6009DB3AA585F98767" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherCurrentLiabilitiesMember" xlink:label="loc_us-gaap_OtherCurrentLiabilitiesMember_A6C1B6204832DD30E2463AA585F9E5B3" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_1E3AEFE37459555776783AA585F95F18" xlink:to="loc_us-gaap_OtherCurrentLiabilitiesMember_A6C1B6204832DD30E2463AA585F9E5B3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesMember" xlink:label="loc_us-gaap_OtherNoncurrentLiabilitiesMember_1A717EC7D2D88A48F5E23AA585FA2B5F" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_1E3AEFE37459555776783AA585F95F18" xlink:to="loc_us-gaap_OtherNoncurrentLiabilitiesMember_1A717EC7D2D88A48F5E23AA585FA2B5F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_3C3D8FF7832F334300763AA585FAF74A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_0BC0883237F14647584A3AA585FA397D" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_3C3D8FF7832F334300763AA585FAF74A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_636F34A02E96427AB1463AA585FA604E" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_0BC0883237F14647584A3AA585FA397D" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_636F34A02E96427AB1463AA585FA604E" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/FinancialInstrumentsNarrativeDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GuaranteeObligationsLineItems" xlink:label="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfGuaranteeObligationsTable" xlink:label="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_DC9F969BA8D288482910591AA478E0D5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_DC9F969BA8D288482910591AA478E0D5" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_570A2822D7CC75E4FE5B591AA479CD09" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_DC9F969BA8D288482910591AA478E0D5" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_570A2822D7CC75E4FE5B591AA479CD09" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_8E71C770B8B7CE91384D591AA479E059_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_570A2822D7CC75E4FE5B591AA479CD09" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_8E71C770B8B7CE91384D591AA479E059_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_8E71C770B8B7CE91384D591AA479E059" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_570A2822D7CC75E4FE5B591AA479CD09" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_8E71C770B8B7CE91384D591AA479E059" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember" xlink:label="loc_hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember_626E6DA46ABF51524BAD591AA479665F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_8E71C770B8B7CE91384D591AA479E059" xlink:to="loc_hsc_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationMember_626E6DA46ABF51524BAD591AA479665F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtConversionByUniqueDescriptionAxis" xlink:label="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_5F8B2E58D601AC0C54D8591AA47975F8" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_DC9F969BA8D288482910591AA478E0D5" xlink:to="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_5F8B2E58D601AC0C54D8591AA47975F8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtConversionNameDomain" xlink:label="loc_us-gaap_DebtConversionNameDomain_14184DA62DB7942F50AA591AA47A58ED_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_5F8B2E58D601AC0C54D8591AA47975F8" xlink:to="loc_us-gaap_DebtConversionNameDomain_14184DA62DB7942F50AA591AA47A58ED_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtConversionNameDomain" xlink:label="loc_us-gaap_DebtConversionNameDomain_14184DA62DB7942F50AA591AA47A58ED" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtConversionByUniqueDescriptionAxis_5F8B2E58D601AC0C54D8591AA47975F8" xlink:to="loc_us-gaap_DebtConversionNameDomain_14184DA62DB7942F50AA591AA47A58ED" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_FloatingRateToFixedRateMember" xlink:label="loc_hsc_FloatingRateToFixedRateMember_1BF0CA9B7FCFE6004CA1591AA47AE0F0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtConversionNameDomain_14184DA62DB7942F50AA591AA47A58ED" xlink:to="loc_hsc_FloatingRateToFixedRateMember_1BF0CA9B7FCFE6004CA1591AA47AE0F0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GuaranteeObligationsByNatureAxis" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis_4288745AA07E6BA96126591AA47A81D1" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_DC9F969BA8D288482910591AA478E0D5" xlink:to="loc_us-gaap_GuaranteeObligationsByNatureAxis_4288745AA07E6BA96126591AA47A81D1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GuaranteeObligationsNatureDomain" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_BB911C9D7797D880DBC3591AA47AA8EF_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_4288745AA07E6BA96126591AA47A81D1" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_BB911C9D7797D880DBC3591AA47AA8EF_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GuaranteeObligationsNatureDomain" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_BB911C9D7797D880DBC3591AA47AA8EF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_4288745AA07E6BA96126591AA47A81D1" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_BB911C9D7797D880DBC3591AA47AA8EF" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_StandbyLettersOfCreditBondsAndBankGuaranteesMember" xlink:label="loc_hsc_StandbyLettersOfCreditBondsAndBankGuaranteesMember_C827DB4B7B50E0E7AC49591AA47BCF9E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_BB911C9D7797D880DBC3591AA47AA8EF" xlink:to="loc_hsc_StandbyLettersOfCreditBondsAndBankGuaranteesMember_C827DB4B7B50E0E7AC49591AA47BCF9E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_NetWorkingCapitalSettlementMember" xlink:label="loc_hsc_NetWorkingCapitalSettlementMember_483FDFA339C62BE070BC591AA47B025E" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_BB911C9D7797D880DBC3591AA47AA8EF" xlink:to="loc_hsc_NetWorkingCapitalSettlementMember_483FDFA339C62BE070BC591AA47B025E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IndemnificationGuaranteeMember" xlink:label="loc_us-gaap_IndemnificationGuaranteeMember_4ACC783BC64DB122361D591AA47BC71D" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_BB911C9D7797D880DBC3591AA47AA8EF" xlink:to="loc_us-gaap_IndemnificationGuaranteeMember_4ACC783BC64DB122361D591AA47BC71D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_AEA89431BC5B16EA3567591AA47BCD3C" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_DC9F969BA8D288482910591AA478E0D5" xlink:to="loc_srt_RangeAxis_AEA89431BC5B16EA3567591AA47BCD3C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_077E7ACB9E68B957EABB591AA47BBF04_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_AEA89431BC5B16EA3567591AA47BCD3C" xlink:to="loc_srt_RangeMember_077E7ACB9E68B957EABB591AA47BBF04_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_077E7ACB9E68B957EABB591AA47BBF04" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_AEA89431BC5B16EA3567591AA47BCD3C" xlink:to="loc_srt_RangeMember_077E7ACB9E68B957EABB591AA47BBF04" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_045E6CCF4E6B4EBB9932591AA47CB258" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_077E7ACB9E68B957EABB591AA47BBF04" xlink:to="loc_srt_MinimumMember_045E6CCF4E6B4EBB9932591AA47CB258" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_E100C49CF04DA3686797591AA47C8801" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_077E7ACB9E68B957EABB591AA47BBF04" xlink:to="loc_srt_MaximumMember_E100C49CF04DA3686797591AA47C8801" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_F04C5D75E5C62D75DD70591AA47C8B76" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_DC9F969BA8D288482910591AA478E0D5" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_F04C5D75E5C62D75DD70591AA47C8B76" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_F361A49BCB8D9A92F43E591AA47C7B2A_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_F04C5D75E5C62D75DD70591AA47C8B76" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_F361A49BCB8D9A92F43E591AA47C7B2A_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_F361A49BCB8D9A92F43E591AA47C7B2A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_F04C5D75E5C62D75DD70591AA47C8B76" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_F361A49BCB8D9A92F43E591AA47C7B2A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SubjecttoMasterNettingAgreementsMember" xlink:label="loc_hsc_SubjecttoMasterNettingAgreementsMember_B9272CBC2DFDA0016A7F591AA47D6840" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_F361A49BCB8D9A92F43E591AA47C7B2A" xlink:to="loc_hsc_SubjecttoMasterNettingAgreementsMember_B9272CBC2DFDA0016A7F591AA47D6840" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignExchangeForwardMember" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_3FD537C816B68BE26B38591AA47D9522" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_F361A49BCB8D9A92F43E591AA47C7B2A" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_3FD537C816B68BE26B38591AA47D9522" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="loc_us-gaap_InterestRateSwapMember_8EB97630BEA07C62F97C591AA47DFBA0" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_F361A49BCB8D9A92F43E591AA47C7B2A" xlink:to="loc_us-gaap_InterestRateSwapMember_8EB97630BEA07C62F97C591AA47DFBA0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_StatementScenarioAxis" xlink:label="loc_srt_StatementScenarioAxis_43EFA02F90AD57DE74B8591AA47D0FC0" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_DC9F969BA8D288482910591AA478E0D5" xlink:to="loc_srt_StatementScenarioAxis_43EFA02F90AD57DE74B8591AA47D0FC0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srt_ScenarioUnspecifiedDomain_27435A11C3A52A685667591AA47DED7C_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_43EFA02F90AD57DE74B8591AA47D0FC0" xlink:to="loc_srt_ScenarioUnspecifiedDomain_27435A11C3A52A685667591AA47DED7C_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srt_ScenarioUnspecifiedDomain_27435A11C3A52A685667591AA47DED7C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_43EFA02F90AD57DE74B8591AA47D0FC0" xlink:to="loc_srt_ScenarioUnspecifiedDomain_27435A11C3A52A685667591AA47DED7C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ScenarioForecastMember" xlink:label="loc_srt_ScenarioForecastMember_812F6217D77BB2503F25591AA47E4FC7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_27435A11C3A52A685667591AA47DED7C" xlink:to="loc_srt_ScenarioForecastMember_812F6217D77BB2503F25591AA47E4FC7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="loc_us-gaap_VariableRateAxis_BA3E3468B5745F309F0F591AA47E2156" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_DC9F969BA8D288482910591AA478E0D5" xlink:to="loc_us-gaap_VariableRateAxis_BA3E3468B5745F309F0F591AA47E2156" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_B98FA02F42CB0A00A993591AA47E276B_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_BA3E3468B5745F309F0F591AA47E2156" xlink:to="loc_us-gaap_VariableRateDomain_B98FA02F42CB0A00A993591AA47E276B_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_B98FA02F42CB0A00A993591AA47E276B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_BA3E3468B5745F309F0F591AA47E2156" xlink:to="loc_us-gaap_VariableRateDomain_B98FA02F42CB0A00A993591AA47E276B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_0DB833F8783E52B11585591AA47FAB77" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_B98FA02F42CB0A00A993591AA47E276B" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_0DB833F8783E52B11585591AA47FAB77" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_BFBDC96ADDA00D805F28591AA47FD5F0" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_DC9F969BA8D288482910591AA478E0D5" xlink:to="loc_us-gaap_DebtInstrumentAxis_BFBDC96ADDA00D805F28591AA47FD5F0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_E997F496126742DCB577591AA47F5CF8_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_BFBDC96ADDA00D805F28591AA47FD5F0" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_E997F496126742DCB577591AA47F5CF8_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_E997F496126742DCB577591AA47F5CF8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_BFBDC96ADDA00D805F28591AA47FD5F0" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_E997F496126742DCB577591AA47F5CF8" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TermLoanFacilityFixedRateMember" xlink:label="loc_hsc_TermLoanFacilityFixedRateMember_6FF0204DC64AA1AAE540591AA47FB9F6" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_E997F496126742DCB577591AA47F5CF8" xlink:to="loc_hsc_TermLoanFacilityFixedRateMember_6FF0204DC64AA1AAE540591AA47FB9F6" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_CA411F511FDDED406411591AA4800C11" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGuaranteeObligationsTable_DC9F969BA8D288482910591AA478E0D5" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_CA411F511FDDED406411591AA4800C11" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_7F7D1C4FD15A9BF937A6591AA480B366_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_CA411F511FDDED406411591AA4800C11" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_7F7D1C4FD15A9BF937A6591AA480B366_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_7F7D1C4FD15A9BF937A6591AA480B366" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_CA411F511FDDED406411591AA4800C11" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_7F7D1C4FD15A9BF937A6591AA480B366" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TermLoanMember" xlink:label="loc_hsc_TermLoanMember_78208BBD37AD67FAACBB591AA48068BC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_7F7D1C4FD15A9BF937A6591AA480B366" xlink:to="loc_hsc_TermLoanMember_78208BBD37AD67FAACBB591AA48068BC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability" xlink:label="loc_us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability_D5BFB92BC080E725C97A591AA480EA5F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability_D5BFB92BC080E725C97A591AA480EA5F" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_GuaranteeObligationsTerm1" xlink:label="loc_hsc_GuaranteeObligationsTerm1_D87C211291117A9803E4591AA48176DD" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_hsc_GuaranteeObligationsTerm1_D87C211291117A9803E4591AA48176DD" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_GuaranteeObligationsAnnualFeePercentage" xlink:label="loc_hsc_GuaranteeObligationsAnnualFeePercentage_B2B7EAAF22069FBBEB84591AA4811E7F" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_hsc_GuaranteeObligationsAnnualFeePercentage_B2B7EAAF22069FBBEB84591AA4811E7F" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_NumberOfCountriesInWhichEntityHasCurrencyExposures" xlink:label="loc_hsc_NumberOfCountriesInWhichEntityHasCurrencyExposures_EEA47CAAAB16813AFE87591AA4817587" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_hsc_NumberOfCountriesInWhichEntityHasCurrencyExposures_EEA47CAAAB16813AFE87591AA4817587" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_GuaranteeObligationsRemainingTerm" xlink:label="loc_hsc_GuaranteeObligationsRemainingTerm_7235F1AD627710043A5E591AA48146AB" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_hsc_GuaranteeObligationsRemainingTerm_7235F1AD627710043A5E591AA48146AB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GuaranteeObligationsMaximumExposure" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_8080FB82CCB3CCCBF1C4591AA481F895" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_8080FB82CCB3CCCBF1C4591AA481F895" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GuaranteeObligationsCurrentCarryingValue" xlink:label="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_893BD63FA0016A5EDCCB591AA482FE21" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_893BD63FA0016A5EDCCB591AA482FE21" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeNet" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeNet_62D990EE0F3E3A15E4AE591AA48288CA" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeNet_62D990EE0F3E3A15E4AE591AA48288CA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeNotionalAmount" xlink:label="loc_us-gaap_DerivativeNotionalAmount_7FC7E4C5750701C88803591AA4829047" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_DerivativeNotionalAmount_7FC7E4C5750701C88803591AA4829047" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TranslationAdjustmentForNetInvestmentHedgeIncreaseDecreaseNetOfTax" xlink:label="loc_us-gaap_TranslationAdjustmentForNetInvestmentHedgeIncreaseDecreaseNetOfTax_2DDBF75A04440E2D398C591AA482D920" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_TranslationAdjustmentForNetInvestmentHedgeIncreaseDecreaseNetOfTax_2DDBF75A04440E2D398C591AA482D920" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_A782A32FF8634BD25C5B591AA4825BC0" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_A782A32FF8634BD25C5B591AA4825BC0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_D6BCF46304319FBD4A93591AA482626E" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_D6BCF46304319FBD4A93591AA482626E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtConversionOriginalDebtAmount1" xlink:label="loc_us-gaap_DebtConversionOriginalDebtAmount1_AB2A7E8E7FD645ACD5B0591AA483FC34" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_DebtConversionOriginalDebtAmount1_AB2A7E8E7FD645ACD5B0591AA483FC34" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:label="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit_35D29CF748650FCCE78E591AA4837CCC" xlink:type="locator"/>
<link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_RepaymentsOfLongTermLinesOfCredit_35D29CF748650FCCE78E591AA4837CCC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet" xlink:label="loc_us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet_0F6987E0F4F9A616CAF2591AA4837E13" xlink:type="locator"/>
<link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet_0F6987E0F4F9A616CAF2591AA4837E13" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebtFairValue" xlink:label="loc_us-gaap_LongTermDebtFairValue_F327659D30010300A0E4591AA483D569" xlink:type="locator"/>
<link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_LongTermDebtFairValue_F327659D30010300A0E4591AA483D569" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_C716AFD80AB9216C80C4591AA4833A1B" xlink:type="locator"/>
<link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsLineItems_750EE3672BC20EFEDFED591AA480263C" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_C716AFD80AB9216C80C4591AA4833A1B" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/FinancialInstrumentsTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/GoodwillAndOtherIntangibleAssets" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/GoodwillAndOtherIntangibleAssetsDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GoodwillLineItems" xlink:label="loc_us-gaap_GoodwillLineItems_74244C0EC69CE9F3A7845F8AEA9384FB" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfGoodwillTable" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_C0EDCA1B877BACD36CA85F8AEA9191F2" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_74244C0EC69CE9F3A7845F8AEA9384FB" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_C0EDCA1B877BACD36CA85F8AEA9191F2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_7FD528CA30120DDBBEA05F8AEA9190FC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_C0EDCA1B877BACD36CA85F8AEA9191F2" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_7FD528CA30120DDBBEA05F8AEA9190FC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_C67FDEC2E622FC96AD6B5F8AEA91157D_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7FD528CA30120DDBBEA05F8AEA9190FC" xlink:to="loc_us-gaap_SegmentDomain_C67FDEC2E622FC96AD6B5F8AEA91157D_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_C67FDEC2E622FC96AD6B5F8AEA91157D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7FD528CA30120DDBBEA05F8AEA9190FC" xlink:to="loc_us-gaap_SegmentDomain_C67FDEC2E622FC96AD6B5F8AEA91157D" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoEnvironmentalSegmentMember" xlink:label="loc_hsc_HarscoEnvironmentalSegmentMember_47C43A8A2CA532C0D6FB5F8AEA9284EF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C67FDEC2E622FC96AD6B5F8AEA91157D" xlink:to="loc_hsc_HarscoEnvironmentalSegmentMember_47C43A8A2CA532C0D6FB5F8AEA9284EF" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_ECB4F5F0F78A6577D81D5F8AEA921B1B" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C67FDEC2E622FC96AD6B5F8AEA91157D" xlink:to="loc_hsc_CleanEarthMember_ECB4F5F0F78A6577D81D5F8AEA921B1B" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoRailMember" xlink:label="loc_hsc_HarscoRailMember_A3D2DD7B8BA9167CA16D5F8AEA938715" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C67FDEC2E622FC96AD6B5F8AEA91157D" xlink:to="loc_hsc_HarscoRailMember_A3D2DD7B8BA9167CA16D5F8AEA938715" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GoodwillRollForward" xlink:label="loc_us-gaap_GoodwillRollForward_220A6A095F0F07965AC45F8AEA93DCBF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_74244C0EC69CE9F3A7845F8AEA9384FB" xlink:to="loc_us-gaap_GoodwillRollForward_220A6A095F0F07965AC45F8AEA93DCBF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_3804C562496FAAD305535F8AEA937882" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_220A6A095F0F07965AC45F8AEA93DCBF" xlink:to="loc_us-gaap_Goodwill_3804C562496FAAD305535F8AEA937882" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GoodwillOtherIncreaseDecrease" xlink:label="loc_us-gaap_GoodwillOtherIncreaseDecrease_0CDE4520C28176CF963F5F8AEA939038" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_220A6A095F0F07965AC45F8AEA93DCBF" xlink:to="loc_us-gaap_GoodwillOtherIncreaseDecrease_0CDE4520C28176CF963F5F8AEA939038" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GoodwillForeignCurrencyTranslationGainLoss" xlink:label="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_39765D94E2A23DD9E4735F8AEA93DE94" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_220A6A095F0F07965AC45F8AEA93DCBF" xlink:to="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_39765D94E2A23DD9E4735F8AEA93DE94" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/GoodwillAndOtherIntangibleAssetsDetails2" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0CA6AA378179D4550E2D5993E3CEAEFB" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable" xlink:label="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_783784AFA6C260A646C35993E3CBE60A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0CA6AA378179D4550E2D5993E3CEAEFB" xlink:to="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_783784AFA6C260A646C35993E3CBE60A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8BB0A5B71DF7A71C5C3C5993E3CC7821" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_783784AFA6C260A646C35993E3CBE60A" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8BB0A5B71DF7A71C5C3C5993E3CC7821" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_055FB0A0A6D28C8E5FDD5993E3CC7B03_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8BB0A5B71DF7A71C5C3C5993E3CC7821" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_055FB0A0A6D28C8E5FDD5993E3CC7B03_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_055FB0A0A6D28C8E5FDD5993E3CC7B03" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8BB0A5B71DF7A71C5C3C5993E3CC7821" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_055FB0A0A6D28C8E5FDD5993E3CC7B03" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CustomerRelatedIntangibleAssetsMember" xlink:label="loc_us-gaap_CustomerRelatedIntangibleAssetsMember_75FF446CDDEC6C414F145993E3CCCD2E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_055FB0A0A6D28C8E5FDD5993E3CC7B03" xlink:to="loc_us-gaap_CustomerRelatedIntangibleAssetsMember_75FF446CDDEC6C414F145993E3CCCD2E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_PermitsAndRightsMember" xlink:label="loc_hsc_PermitsAndRightsMember_FE3DABF15BF2780728DD5993E3CC682A" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_055FB0A0A6D28C8E5FDD5993E3CC7B03" xlink:to="loc_hsc_PermitsAndRightsMember_FE3DABF15BF2780728DD5993E3CC682A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PatentsMember" xlink:label="loc_us-gaap_PatentsMember_262A53F48322E22DB83A5993E3CDEB6D" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_055FB0A0A6D28C8E5FDD5993E3CC7B03" xlink:to="loc_us-gaap_PatentsMember_262A53F48322E22DB83A5993E3CDEB6D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnpatentedTechnologyMember" xlink:label="loc_us-gaap_UnpatentedTechnologyMember_91D8719DDB6A521AF71E5993E3CDE5FA" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_055FB0A0A6D28C8E5FDD5993E3CC7B03" xlink:to="loc_us-gaap_UnpatentedTechnologyMember_91D8719DDB6A521AF71E5993E3CDE5FA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TradeNamesMember" xlink:label="loc_us-gaap_TradeNamesMember_6AE33D0D638CC127E07E5993E3CD8598" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_055FB0A0A6D28C8E5FDD5993E3CC7B03" xlink:to="loc_us-gaap_TradeNamesMember_6AE33D0D638CC127E07E5993E3CD8598" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherIntangibleAssetsMember" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_6CC061D7DCC3643469975993E3CDB423" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_055FB0A0A6D28C8E5FDD5993E3CC7B03" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_6CC061D7DCC3643469975993E3CDB423" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AirRightsMember" xlink:label="loc_hsc_AirRightsMember_421827ECC02B5684706F5993E3CDF5D4" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_055FB0A0A6D28C8E5FDD5993E3CC7B03" xlink:to="loc_hsc_AirRightsMember_421827ECC02B5684706F5993E3CDF5D4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_0CDBE7081CE52280E3885993E3CE6B45" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0CA6AA378179D4550E2D5993E3CEAEFB" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_0CDBE7081CE52280E3885993E3CE6B45" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_100C67EA44E43CE5BFAC5993E3CE47B0" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0CA6AA378179D4550E2D5993E3CEAEFB" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_100C67EA44E43CE5BFAC5993E3CE47B0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_73CA243A52E9867F23375993E3CEF36F" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0CA6AA378179D4550E2D5993E3CEAEFB" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_73CA243A52E9867F23375993E3CEF36F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_D3540A0906E1B00D43725993E3CEA4F3" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_0CA6AA378179D4550E2D5993E3CEAEFB" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_D3540A0906E1B00D43725993E3CEA4F3" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/GoodwillAndOtherIntangibleAssetsTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/IncomeTaxes" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/IncomeTaxesDetails" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/IncomeTaxesDetails2" xlink:type="extended">
<link:loc xlink:href="hsc-20191231.xsd#hsc_IncomeTaxDisclosureLineItems" xlink:label="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:type="locator"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_IncomeTaxDisclosureTable" xlink:label="loc_hsc_IncomeTaxDisclosureTable_D622FDCC3A9293D566B962F83E70362A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_hsc_IncomeTaxDisclosureTable_D622FDCC3A9293D566B962F83E70362A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="loc_srt_StatementGeographicalAxis_BED2FD80182FBF68AEE762F83E707A23" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_hsc_IncomeTaxDisclosureTable_D622FDCC3A9293D566B962F83E70362A" xlink:to="loc_srt_StatementGeographicalAxis_BED2FD80182FBF68AEE762F83E707A23" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_82285497132750297CA762F83E70B997_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_BED2FD80182FBF68AEE762F83E707A23" xlink:to="loc_srt_SegmentGeographicalDomain_82285497132750297CA762F83E70B997_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_82285497132750297CA762F83E70B997" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_BED2FD80182FBF68AEE762F83E707A23" xlink:to="loc_srt_SegmentGeographicalDomain_82285497132750297CA762F83E70B997" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_US" xlink:label="loc_country_US_4F0258A0B7AB700DCE7D62F83E710DC1" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_82285497132750297CA762F83E70B997" xlink:to="loc_country_US_4F0258A0B7AB700DCE7D62F83E710DC1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_B3B368841082168C072962F83E718CE5" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_hsc_IncomeTaxDisclosureTable_D622FDCC3A9293D566B962F83E70362A" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_B3B368841082168C072962F83E718CE5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_C167DD3C2371CFB07D7362F83E71E8B1_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_B3B368841082168C072962F83E718CE5" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_C167DD3C2371CFB07D7362F83E71E8B1_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_C167DD3C2371CFB07D7362F83E71E8B1" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_B3B368841082168C072962F83E718CE5" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_C167DD3C2371CFB07D7362F83E71E8B1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignCountryMember" xlink:label="loc_us-gaap_ForeignCountryMember_B1E495A6B11EAB7C0A4462F83E727B2A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_C167DD3C2371CFB07D7362F83E71E8B1" xlink:to="loc_us-gaap_ForeignCountryMember_B1E495A6B11EAB7C0A4462F83E727B2A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_9629C84C80C8B5C6D07362F83E723AF4" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_C167DD3C2371CFB07D7362F83E71E8B1" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_9629C84C80C8B5C6D07362F83E723AF4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxPeriodAxis" xlink:label="loc_us-gaap_TaxPeriodAxis_E2AC57082CA40C3ADEF762F83E7243BB" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_hsc_IncomeTaxDisclosureTable_D622FDCC3A9293D566B962F83E70362A" xlink:to="loc_us-gaap_TaxPeriodAxis_E2AC57082CA40C3ADEF762F83E7243BB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:label="loc_us-gaap_TaxPeriodDomain_E3C166CE236249E0D91362F83E722A8B_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TaxPeriodAxis_E2AC57082CA40C3ADEF762F83E7243BB" xlink:to="loc_us-gaap_TaxPeriodDomain_E3C166CE236249E0D91362F83E722A8B_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:label="loc_us-gaap_TaxPeriodDomain_E3C166CE236249E0D91362F83E722A8B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TaxPeriodAxis_E2AC57082CA40C3ADEF762F83E7243BB" xlink:to="loc_us-gaap_TaxPeriodDomain_E3C166CE236249E0D91362F83E722A8B" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TaxYears2030Through2034Member" xlink:label="loc_hsc_TaxYears2030Through2034Member_2ECDC1D686B4A578F4F362F83E722612" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_E3C166CE236249E0D91362F83E722A8B" xlink:to="loc_hsc_TaxYears2030Through2034Member_2ECDC1D686B4A578F4F362F83E722612" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_2CA38CF2304C24FD160662F83E724E45" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_hsc_IncomeTaxDisclosureTable_D622FDCC3A9293D566B962F83E70362A" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_2CA38CF2304C24FD160662F83E724E45" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_6437A1D7DD81E20963B462F83E72DD2E_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_2CA38CF2304C24FD160662F83E724E45" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_6437A1D7DD81E20963B462F83E72DD2E_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_6437A1D7DD81E20963B462F83E72DD2E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_2CA38CF2304C24FD160662F83E724E45" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_6437A1D7DD81E20963B462F83E72DD2E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TaxCutsAndJobsActof2017ImpactIncludingLowerTaxRateOnU.S.IncomeTaxExpense" xlink:label="loc_hsc_TaxCutsAndJobsActof2017ImpactIncludingLowerTaxRateOnU.S.IncomeTaxExpense_C38F4A88CBCC594DEB5962F83E72B673" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_hsc_TaxCutsAndJobsActof2017ImpactIncludingLowerTaxRateOnU.S.IncomeTaxExpense_C38F4A88CBCC594DEB5962F83E72B673" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Amount" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Amount_6D140F316A0F062E65D362F83E728161" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Amount_6D140F316A0F062E65D362F83E728161" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign_D9A5FE90674E51F4987862F83E725855" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign_D9A5FE90674E51F4987862F83E725855" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_Differencesoninternationalearningsandremittances" xlink:label="loc_hsc_Differencesoninternationalearningsandremittances_3636DCF7F3A22080865562F83E725174" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_hsc_Differencesoninternationalearningsandremittances_3636DCF7F3A22080865562F83E725174" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations" xlink:label="loc_us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations_059A92C2D0BC319DE91062F83E722CCA" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations_059A92C2D0BC319DE91062F83E722CCA" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TaxCutsAndJobsActOf2017IncompleteAccountingChangeInTaxRateDeferredTaxAssetRevaluingDomesticNetDeferredTaxAssetProvisionalIncomeTaxExpense" xlink:label="loc_hsc_TaxCutsAndJobsActOf2017IncompleteAccountingChangeInTaxRateDeferredTaxAssetRevaluingDomesticNetDeferredTaxAssetProvisionalIncomeTaxExpense_DC1C0E9D7337C09D056162F83E726269" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_hsc_TaxCutsAndJobsActOf2017IncompleteAccountingChangeInTaxRateDeferredTaxAssetRevaluingDomesticNetDeferredTaxAssetProvisionalIncomeTaxExpense_DC1C0E9D7337C09D056162F83E726269" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_12A780256B7FF063D66B62F83E72ABB4" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_12A780256B7FF063D66B62F83E72ABB4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration_A4E27431B267A53780A162F83E726792" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration_A4E27431B267A53780A162F83E726792" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration_6833EDEECD85C07E389C62F83E72AEC2" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration_6833EDEECD85C07E389C62F83E72AEC2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsCapitalLossCarryforwards" xlink:label="loc_us-gaap_DeferredTaxAssetsCapitalLossCarryforwards_B61DEC156913E2F699AD62F83E72D984" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_DeferredTaxAssetsCapitalLossCarryforwards_B61DEC156913E2F699AD62F83E72D984" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="loc_us-gaap_DeferredTaxAssetsValuationAllowance_7CFF0F08E30E3E8C0B4F62F83E76DE7E" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_DeferredTaxAssetsValuationAllowance_7CFF0F08E30E3E8C0B4F62F83E76DE7E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TaxCutsAndJobsActOf2017ChangeInTaxRateDeferredTaxAssetValuationAllowanceTaxCreditCarryforward" xlink:label="loc_hsc_TaxCutsAndJobsActOf2017ChangeInTaxRateDeferredTaxAssetValuationAllowanceTaxCreditCarryforward_5A74663261B64F27FF8C62F83E768D6E" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_hsc_TaxCutsAndJobsActOf2017ChangeInTaxRateDeferredTaxAssetValuationAllowanceTaxCreditCarryforward_5A74663261B64F27FF8C62F83E768D6E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DeferredTaxAssetsValuationAllowanceDecreaseDuetoAltekAcquisition" xlink:label="loc_hsc_DeferredTaxAssetsValuationAllowanceDecreaseDuetoAltekAcquisition_E0ACF093F6222FC3532062F83E76AD72" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_hsc_DeferredTaxAssetsValuationAllowanceDecreaseDuetoAltekAcquisition_E0ACF093F6222FC3532062F83E76AD72" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DeferredTaxAssetsValuationAllowanceIncreaseDecreaseFromForeignCurrencyTranslation" xlink:label="loc_hsc_DeferredTaxAssetsValuationAllowanceIncreaseDecreaseFromForeignCurrencyTranslation_1F786CC7C7313754DAFC62F83E76F4A2" xlink:type="locator"/>
<link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_hsc_DeferredTaxAssetsValuationAllowanceIncreaseDecreaseFromForeignCurrencyTranslation_1F786CC7C7313754DAFC62F83E76F4A2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_D82ACA10A38BD5DE6F5062F83E7631BA" xlink:type="locator"/>
<link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_D82ACA10A38BD5DE6F5062F83E7631BA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_F0948C5084C238A91B8562F83E763939" xlink:type="locator"/>
<link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_F0948C5084C238A91B8562F83E763939" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit" xlink:label="loc_us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit_FA6FEF169EC7D19D1A0862F83E766894" xlink:type="locator"/>
<link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit_FA6FEF169EC7D19D1A0862F83E766894" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ValuationallowanceadjustmentrelatedtotheacquisitionofAltek" xlink:label="loc_hsc_ValuationallowanceadjustmentrelatedtotheacquisitionofAltek_78977BBDFD905B1FAD1262F83E7630F2" xlink:type="locator"/>
<link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_hsc_ValuationallowanceadjustmentrelatedtotheacquisitionofAltek_78977BBDFD905B1FAD1262F83E7630F2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CurrentForeignTaxExpenseBenefit" xlink:label="loc_us-gaap_CurrentForeignTaxExpenseBenefit_4786404CEC49E9037E3462F83E76AE19" xlink:type="locator"/>
<link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_IncomeTaxDisclosureLineItems_8DA737226738A5E60F5062F83E72D3A7" xlink:to="loc_us-gaap_CurrentForeignTaxExpenseBenefit_4786404CEC49E9037E3462F83E76AE19" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/IncomeTaxesDetails3" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/IncomeTaxesDetails4" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLossCarryforwardsLineItems" xlink:label="loc_us-gaap_OperatingLossCarryforwardsLineItems_914B9FCB1F756FB0F813554790C271DD" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLossCarryforwardsTable" xlink:label="loc_us-gaap_OperatingLossCarryforwardsTable_6D9D9DE2EABDC9BDCFA5554790BD25BB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_914B9FCB1F756FB0F813554790C271DD" xlink:to="loc_us-gaap_OperatingLossCarryforwardsTable_6D9D9DE2EABDC9BDCFA5554790BD25BB" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_6A67A5380CB04C2B51AA554790BDDF07" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_6D9D9DE2EABDC9BDCFA5554790BD25BB" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_6A67A5380CB04C2B51AA554790BDDF07" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_80A6D6A3CA9948532D89554790BDCE87_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_6A67A5380CB04C2B51AA554790BDDF07" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_80A6D6A3CA9948532D89554790BDCE87_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_80A6D6A3CA9948532D89554790BDCE87" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_6A67A5380CB04C2B51AA554790BDDF07" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_80A6D6A3CA9948532D89554790BDCE87" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DomesticCountryMember" xlink:label="loc_us-gaap_DomesticCountryMember_C271DCD5A338BC77F8A5554790BEA1EE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_80A6D6A3CA9948532D89554790BDCE87" xlink:to="loc_us-gaap_DomesticCountryMember_C271DCD5A338BC77F8A5554790BEA1EE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_05361462AF7C8E5C1CE9554790BF5161" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DomesticCountryMember_C271DCD5A338BC77F8A5554790BEA1EE" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_05361462AF7C8E5C1CE9554790BF5161" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignCountryMember" xlink:label="loc_us-gaap_ForeignCountryMember_F3B05DBB4604F32A435E554790BF579B" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_80A6D6A3CA9948532D89554790BDCE87" xlink:to="loc_us-gaap_ForeignCountryMember_F3B05DBB4604F32A435E554790BF579B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityNameAxis" xlink:label="loc_us-gaap_IncomeTaxAuthorityNameAxis_194A277D854D9F255146554790C0DF97" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_6D9D9DE2EABDC9BDCFA5554790BD25BB" xlink:to="loc_us-gaap_IncomeTaxAuthorityNameAxis_194A277D854D9F255146554790C0DF97" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityNameDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityNameDomain_3AF4FF2D0C2F250FE00F554790C08427_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityNameAxis_194A277D854D9F255146554790C0DF97" xlink:to="loc_us-gaap_IncomeTaxAuthorityNameDomain_3AF4FF2D0C2F250FE00F554790C08427_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityNameDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityNameDomain_3AF4FF2D0C2F250FE00F554790C08427" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityNameAxis_194A277D854D9F255146554790C0DF97" xlink:to="loc_us-gaap_IncomeTaxAuthorityNameDomain_3AF4FF2D0C2F250FE00F554790C08427" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxPeriodAxis" xlink:label="loc_us-gaap_TaxPeriodAxis_944892D6EF1C6391E933554790C0BE15" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_6D9D9DE2EABDC9BDCFA5554790BD25BB" xlink:to="loc_us-gaap_TaxPeriodAxis_944892D6EF1C6391E933554790C0BE15" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:label="loc_us-gaap_TaxPeriodDomain_2855D6ADFBF8A0B40614554790C12F93_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TaxPeriodAxis_944892D6EF1C6391E933554790C0BE15" xlink:to="loc_us-gaap_TaxPeriodDomain_2855D6ADFBF8A0B40614554790C12F93_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:label="loc_us-gaap_TaxPeriodDomain_2855D6ADFBF8A0B40614554790C12F93" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TaxPeriodAxis_944892D6EF1C6391E933554790C0BE15" xlink:to="loc_us-gaap_TaxPeriodDomain_2855D6ADFBF8A0B40614554790C12F93" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TaxYears2020Through2024Member" xlink:label="loc_hsc_TaxYears2020Through2024Member_1A1853F3D8F40ADD2E50554790C10720" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_2855D6ADFBF8A0B40614554790C12F93" xlink:to="loc_hsc_TaxYears2020Through2024Member_1A1853F3D8F40ADD2E50554790C10720" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TaxYears2025Through2029Member" xlink:label="loc_hsc_TaxYears2025Through2029Member_3DE99F10DF6F1ADA2DD4554790C1CDA5" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_2855D6ADFBF8A0B40614554790C12F93" xlink:to="loc_hsc_TaxYears2025Through2029Member_3DE99F10DF6F1ADA2DD4554790C1CDA5" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TaxYears2030Through2034Member" xlink:label="loc_hsc_TaxYears2030Through2034Member_1DC56D4CC8AAC6144217554790C20D21" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_2855D6ADFBF8A0B40614554790C12F93" xlink:to="loc_hsc_TaxYears2030Through2034Member_1DC56D4CC8AAC6144217554790C20D21" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_TaxYears2035Through2039Member" xlink:label="loc_hsc_TaxYears2035Through2039Member_BFD7B73410C651326620554790C213C4" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_2855D6ADFBF8A0B40614554790C12F93" xlink:to="loc_hsc_TaxYears2035Through2039Member_BFD7B73410C651326620554790C213C4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_51A32015D0B3B1F1D08F554790C3F470" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_914B9FCB1F756FB0F813554790C271DD" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_51A32015D0B3B1F1D08F554790C3F470" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration_1967F8BC1210CBBA8684554790C3E601" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_914B9FCB1F756FB0F813554790C271DD" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration_1967F8BC1210CBBA8684554790C3E601" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_B779A1B30BBAA4E56B4D554790C49C5A" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_914B9FCB1F756FB0F813554790C271DD" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_B779A1B30BBAA4E56B4D554790C49C5A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract" xlink:label="loc_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract_15387CF2F6FD2660626B554790C42DBA" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_914B9FCB1F756FB0F813554790C271DD" xlink:to="loc_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract_15387CF2F6FD2660626B554790C42DBA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ComponentsOfDeferredTaxAssetsAbstract" xlink:label="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract_15387CF2F6FD2660626B554790C42DBA" xlink:to="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment" xlink:label="loc_us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment_45A9503571E179F9E21F554790C45A01" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment_45A9503571E179F9E21F554790C45A01" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities_4DCE9CDE26940D9F7856554790C4917F" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities_4DCE9CDE26940D9F7856554790C4917F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsInventory" xlink:label="loc_us-gaap_DeferredTaxAssetsInventory_8B92FE43D5B7930CB3F6554790C49C13" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsInventory_8B92FE43D5B7930CB3F6554790C49C13" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts_F0F33DDF300CC1DE7167554790C4316E" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts_F0F33DDF300CC1DE7167554790C4316E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_7F5B7FFE2BCEAAD4647D554790C423B1" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_7F5B7FFE2BCEAAD4647D554790C423B1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsForeign" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsForeign_77834450BA4A11292D13554790C45CF1" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsForeign_77834450BA4A11292D13554790C45CF1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsCapitalLossCarryforwards" xlink:label="loc_us-gaap_DeferredTaxAssetsCapitalLossCarryforwards_B6DE6FA6AD35E1957350554790C4A90D" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsCapitalLossCarryforwards_B6DE6FA6AD35E1957350554790C4A90D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions_93E4EBA909E3E582787E554790C442AD" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions_93E4EBA909E3E582787E554790C442AD" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsUnrealizedCurrencyLosses" xlink:label="loc_us-gaap_DeferredTaxAssetsUnrealizedCurrencyLosses_D68F29E8C140AF3B2D56554790C46630" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsUnrealizedCurrencyLosses_D68F29E8C140AF3B2D56554790C46630" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits_3D1ED3933EF2DF62024E554790C4E814" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits_3D1ED3933EF2DF62024E554790C4E814" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost_4A19B53D8E2A5449EF0F554790C415D8" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost_4A19B53D8E2A5449EF0F554790C415D8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsOther" xlink:label="loc_us-gaap_DeferredTaxAssetsOther_89E7B847BC125B987824554790C4B9E1" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsOther_89E7B847BC125B987824554790C4B9E1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxLiabilitiesOther" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesOther_D1319F174DE8909F91C5554790C453CC" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesOther_D1319F174DE8909F91C5554790C453CC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsGross" xlink:label="loc_us-gaap_DeferredTaxAssetsGross_0F3413AB8AF113558C6A554790C80E81" xlink:type="locator"/>
<link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsGross_0F3413AB8AF113558C6A554790C80E81" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="loc_us-gaap_DeferredTaxAssetsValuationAllowance_AA71D6EE862BDA233BDF554790C84C82" xlink:type="locator"/>
<link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsValuationAllowance_AA71D6EE862BDA233BDF554790C84C82" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsNet" xlink:label="loc_us-gaap_DeferredTaxAssetsNet_B13A01149C49576DD3D1554790C84FD2" xlink:type="locator"/>
<link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_C2B103F212D81A3E3830554790C42CE7" xlink:to="loc_us-gaap_DeferredTaxAssetsNet_B13A01149C49576DD3D1554790C84FD2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract" xlink:label="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_42EA3EF17CB08B4D2461554790C8E617" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract_15387CF2F6FD2660626B554790C42DBA" xlink:to="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_42EA3EF17CB08B4D2461554790C8E617" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_D1746D5071BB9C904B30554790C8E47D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_42EA3EF17CB08B4D2461554790C8E617" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_D1746D5071BB9C904B30554790C8E47D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome_340858804035CB574C75554790C8223B" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_42EA3EF17CB08B4D2461554790C8E617" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome_340858804035CB574C75554790C8223B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxLiabilitiesFinancingArrangements" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesFinancingArrangements_0FC60C7297D791329AC6554790C99DA0" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_42EA3EF17CB08B4D2461554790C8E617" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesFinancingArrangements_0FC60C7297D791329AC6554790C99DA0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilities" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilities_92393859AFB7F1273B3C554790C9E2A3" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_42EA3EF17CB08B4D2461554790C8E617" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilities_92393859AFB7F1273B3C554790C9E2A3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNetAbstract" xlink:label="loc_us-gaap_DeferredTaxAssetsLiabilitiesNetAbstract_2A1DB972248370C66517554790C9AA34" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAndLiabilitiesAbstract_15387CF2F6FD2660626B554790C42DBA" xlink:to="loc_us-gaap_DeferredTaxAssetsLiabilitiesNetAbstract_2A1DB972248370C66517554790C9AA34" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsNetNoncurrent" xlink:label="loc_us-gaap_DeferredTaxAssetsNetNoncurrent_868246BAF798B8BB1098554790C9EBEE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredTaxAssetsLiabilitiesNetAbstract_2A1DB972248370C66517554790C9AA34" xlink:to="loc_us-gaap_DeferredTaxAssetsNetNoncurrent_868246BAF798B8BB1098554790C9EBEE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNoncurrent" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_3115BA051C543FF8135E554790CAF7EB" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredTaxAssetsLiabilitiesNetAbstract_2A1DB972248370C66517554790C9AA34" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_3115BA051C543FF8135E554790CAF7EB" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SaleofBusinessesReductionofTaxPaidChangeinCapitalLossCarryforwardsForeignTaxCreditCarryforwardsStateNetOperatingLossCarryforwardsForeignTaxCreditCarryforwards" xlink:label="loc_hsc_SaleofBusinessesReductionofTaxPaidChangeinCapitalLossCarryforwardsForeignTaxCreditCarryforwardsStateNetOperatingLossCarryforwardsForeignTaxCreditCarryforwards_A802563E5A3A1D61E5EE554790CAA95A" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_914B9FCB1F756FB0F813554790C271DD" xlink:to="loc_hsc_SaleofBusinessesReductionofTaxPaidChangeinCapitalLossCarryforwardsForeignTaxCreditCarryforwardsStateNetOperatingLossCarryforwardsForeignTaxCreditCarryforwards_A802563E5A3A1D61E5EE554790CAA95A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration_DE94EF565F65C00BCE90554790CA5DDA" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_914B9FCB1F756FB0F813554790C271DD" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration_DE94EF565F65C00BCE90554790CA5DDA" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_MergerandLiquidationofForeignDormantEntitiesValuationAllowanceReductionReductiontoDeferredTaxAssets" xlink:label="loc_hsc_MergerandLiquidationofForeignDormantEntitiesValuationAllowanceReductionReductiontoDeferredTaxAssets_E725BB7B843D842C6EE2554790CB5B9E" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_914B9FCB1F756FB0F813554790C271DD" xlink:to="loc_hsc_MergerandLiquidationofForeignDormantEntitiesValuationAllowanceReductionReductiontoDeferredTaxAssets_E725BB7B843D842C6EE2554790CB5B9E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:label="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_44E148EC1206439BABF2554790CB92D4" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_914B9FCB1F756FB0F813554790C271DD" xlink:to="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_44E148EC1206439BABF2554790CB92D4" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/IncomeTaxesDetails5" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/IncomeTaxesTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/InformationBySegmentAndGeographicArea" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/InformationBySegmentAndGeographicAreaDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:label="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_F6A48B43878A0C814E695F8AE7AB7E22" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable" xlink:label="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_D7FD96B85C30029E8A0A5F8AE7A3B103" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_F6A48B43878A0C814E695F8AE7AB7E22" xlink:to="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_D7FD96B85C30029E8A0A5F8AE7A3B103" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="loc_srt_StatementGeographicalAxis_BADC85225B1291EA84E35F8AE7AB137E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_D7FD96B85C30029E8A0A5F8AE7A3B103" xlink:to="loc_srt_StatementGeographicalAxis_BADC85225B1291EA84E35F8AE7AB137E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_CE6353745FF0D53A24F75F8AE7AB2500_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_BADC85225B1291EA84E35F8AE7AB137E" xlink:to="loc_srt_SegmentGeographicalDomain_CE6353745FF0D53A24F75F8AE7AB2500_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_CE6353745FF0D53A24F75F8AE7AB2500" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_BADC85225B1291EA84E35F8AE7AB137E" xlink:to="loc_srt_SegmentGeographicalDomain_CE6353745FF0D53A24F75F8AE7AB2500" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_OtherCountriesMember" xlink:label="loc_hsc_OtherCountriesMember_D19508CA866426ADD6D45F8AE7ABA131" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_CE6353745FF0D53A24F75F8AE7AB2500" xlink:to="loc_hsc_OtherCountriesMember_D19508CA866426ADD6D45F8AE7ABA131" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_US" xlink:label="loc_country_US_5BFE8A55373AF23E046C5F8AE7ABA85C" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_CE6353745FF0D53A24F75F8AE7AB2500" xlink:to="loc_country_US_5BFE8A55373AF23E046C5F8AE7ABA85C" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_GB" xlink:label="loc_country_GB_4476A8932D0C3A2A8E535F8AE7ABE04F" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_CE6353745FF0D53A24F75F8AE7AB2500" xlink:to="loc_country_GB_4476A8932D0C3A2A8E535F8AE7ABE04F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_3D17FD517396AB9AE02C5F8AE7AB863C" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_D7FD96B85C30029E8A0A5F8AE7A3B103" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_3D17FD517396AB9AE02C5F8AE7AB863C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_CC9B455943619F7083465F8AE7AB66F9_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3D17FD517396AB9AE02C5F8AE7AB863C" xlink:to="loc_us-gaap_SegmentDomain_CC9B455943619F7083465F8AE7AB66F9_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_CC9B455943619F7083465F8AE7AB66F9" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3D17FD517396AB9AE02C5F8AE7AB863C" xlink:to="loc_us-gaap_SegmentDomain_CC9B455943619F7083465F8AE7AB66F9" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoMetalsAndMineralsMember" xlink:label="loc_hsc_HarscoMetalsAndMineralsMember_A629E310DB3143111F4F5FBC1309EFD7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_CC9B455943619F7083465F8AE7AB66F9" xlink:to="loc_hsc_HarscoMetalsAndMineralsMember_A629E310DB3143111F4F5FBC1309EFD7" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoEnvironmentalSegmentMember" xlink:label="loc_hsc_HarscoEnvironmentalSegmentMember_F19ACBC710FB23EF694F5F8AE7AB82CF" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_CC9B455943619F7083465F8AE7AB66F9" xlink:to="loc_hsc_HarscoEnvironmentalSegmentMember_F19ACBC710FB23EF694F5F8AE7AB82CF" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_4F4AE8D509881C44BBBD5F8AE7AB6862" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_CC9B455943619F7083465F8AE7AB66F9" xlink:to="loc_hsc_CleanEarthMember_4F4AE8D509881C44BBBD5F8AE7AB6862" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoIndustrialMember" xlink:label="loc_hsc_HarscoIndustrialMember_01B8E75F9B55F70B155D5F8AE7AB1323" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_CC9B455943619F7083465F8AE7AB66F9" xlink:to="loc_hsc_HarscoIndustrialMember_01B8E75F9B55F70B155D5F8AE7AB1323" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoRailMember" xlink:label="loc_hsc_HarscoRailMember_AFDFEA3892B4301B107D5F8AE7AB09A6" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_CC9B455943619F7083465F8AE7AB66F9" xlink:to="loc_hsc_HarscoRailMember_AFDFEA3892B4301B107D5F8AE7AB09A6" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_6721DF7DD3503D259AF25F8AE7AB48E8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_F6A48B43878A0C814E695F8AE7AB7E22" xlink:to="loc_us-gaap_Revenues_6721DF7DD3503D259AF25F8AE7AB48E8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:label="loc_us-gaap_NumberOfReportableSegments_62B67E0B42B3EEED679A5F8AE7ABCE23" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_F6A48B43878A0C814E695F8AE7AB7E22" xlink:to="loc_us-gaap_NumberOfReportableSegments_62B67E0B42B3EEED679A5F8AE7ABCE23" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_NumberOfMajorCustomers" xlink:label="loc_hsc_NumberOfMajorCustomers_60D6421E944E9485D58C5F8AE7ABCD58" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_F6A48B43878A0C814E695F8AE7AB7E22" xlink:to="loc_hsc_NumberOfMajorCustomers_60D6421E944E9485D58C5F8AE7ABCD58" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/InformationBySegmentAndGeographicAreaDetails2" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:label="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_DDE08071BBDDEEFA73EE3AE2F80EB803" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_02BBF6E8FB3A799250383AE2F80CAD21" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_DDE08071BBDDEEFA73EE3AE2F80EB803" xlink:to="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_02BBF6E8FB3A799250383AE2F80CAD21" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="loc_srt_StatementGeographicalAxis_9C21CD2D25BEFAA506D83AE2F80CA393" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_02BBF6E8FB3A799250383AE2F80CAD21" xlink:to="loc_srt_StatementGeographicalAxis_9C21CD2D25BEFAA506D83AE2F80CA393" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_6472E6C1DC524BEE1D4F3AE2F80D2435_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_9C21CD2D25BEFAA506D83AE2F80CA393" xlink:to="loc_srt_SegmentGeographicalDomain_6472E6C1DC524BEE1D4F3AE2F80D2435_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_6472E6C1DC524BEE1D4F3AE2F80D2435" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_9C21CD2D25BEFAA506D83AE2F80CA393" xlink:to="loc_srt_SegmentGeographicalDomain_6472E6C1DC524BEE1D4F3AE2F80D2435" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_US" xlink:label="loc_country_US_D177C934BAF23A6848633AE2F80DFE1B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_6472E6C1DC524BEE1D4F3AE2F80D2435" xlink:to="loc_country_US_D177C934BAF23A6848633AE2F80DFE1B" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_GB" xlink:label="loc_country_GB_9F4D58960A3F789E97BF3AE2F80DCF8E" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_6472E6C1DC524BEE1D4F3AE2F80D2435" xlink:to="loc_country_GB_9F4D58960A3F789E97BF3AE2F80DCF8E" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_CN" xlink:label="loc_country_CN_DD6216126FA47D8F0A4B3AE2F80DD76E" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_6472E6C1DC524BEE1D4F3AE2F80D2435" xlink:to="loc_country_CN_DD6216126FA47D8F0A4B3AE2F80DD76E" xlink:type="arc"/>
<link:loc xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_BR" xlink:label="loc_country_BR_1FC75A374F87E92EFB293AE2F80EA166" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_6472E6C1DC524BEE1D4F3AE2F80D2435" xlink:to="loc_country_BR_1FC75A374F87E92EFB293AE2F80EA166" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_OtherCountriesMember" xlink:label="loc_hsc_OtherCountriesMember_56A469A9B92B276978DF3AE2F80EB69A" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_6472E6C1DC524BEE1D4F3AE2F80D2435" xlink:to="loc_hsc_OtherCountriesMember_56A469A9B92B276978DF3AE2F80EB69A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_D12D6B4FADE24C5FAD713AE2F80E701E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_DDE08071BBDDEEFA73EE3AE2F80EB803" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_D12D6B4FADE24C5FAD713AE2F80E701E" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/InformationBySegmentAndGeographicAreaDetails3" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D059FC293499406875505F8AE77C8165" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D059FC293499406875505F8AE77C8165" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsAxis" xlink:label="loc_srt_ConsolidationItemsAxis_3BB64679A9E69D04170D5F8AE77CCBDC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D059FC293499406875505F8AE77C8165" xlink:to="loc_srt_ConsolidationItemsAxis_3BB64679A9E69D04170D5F8AE77CCBDC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsDomain" xlink:label="loc_srt_ConsolidationItemsDomain_433F228C5D3751C6E1195F8AE77CBE23_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_3BB64679A9E69D04170D5F8AE77CCBDC" xlink:to="loc_srt_ConsolidationItemsDomain_433F228C5D3751C6E1195F8AE77CBE23_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsDomain" xlink:label="loc_srt_ConsolidationItemsDomain_433F228C5D3751C6E1195F8AE77CBE23" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_3BB64679A9E69D04170D5F8AE77CCBDC" xlink:to="loc_srt_ConsolidationItemsDomain_433F228C5D3751C6E1195F8AE77CBE23" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:label="loc_us-gaap_OperatingSegmentsMember_992EC390F034495287185F8AE77C68BA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_433F228C5D3751C6E1195F8AE77CBE23" xlink:to="loc_us-gaap_OperatingSegmentsMember_992EC390F034495287185F8AE77C68BA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CorporateNonSegmentMember" xlink:label="loc_us-gaap_CorporateNonSegmentMember_4D927BC4C579D805E2505F8AE77CAE2C" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_433F228C5D3751C6E1195F8AE77CBE23" xlink:to="loc_us-gaap_CorporateNonSegmentMember_4D927BC4C579D805E2505F8AE77CAE2C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_7FC71772BAD8EDA142D95F8AE780507A" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D059FC293499406875505F8AE77C8165" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_7FC71772BAD8EDA142D95F8AE780507A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_75F49B4D886DEE404CE75F8AE780115E_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7FC71772BAD8EDA142D95F8AE780507A" xlink:to="loc_us-gaap_SegmentDomain_75F49B4D886DEE404CE75F8AE780115E_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_75F49B4D886DEE404CE75F8AE780115E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7FC71772BAD8EDA142D95F8AE780507A" xlink:to="loc_us-gaap_SegmentDomain_75F49B4D886DEE404CE75F8AE780115E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoEnvironmentalSegmentMember" xlink:label="loc_hsc_HarscoEnvironmentalSegmentMember_966F60B08858D3B3D7B65F8AE780E09E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_75F49B4D886DEE404CE75F8AE780115E" xlink:to="loc_hsc_HarscoEnvironmentalSegmentMember_966F60B08858D3B3D7B65F8AE780E09E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_38BA2BD5D3180DA66C335F8AE7802F86" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_75F49B4D886DEE404CE75F8AE780115E" xlink:to="loc_hsc_CleanEarthMember_38BA2BD5D3180DA66C335F8AE7802F86" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoIndustrialMember" xlink:label="loc_hsc_HarscoIndustrialMember_4997F4F9E0F0ED27C62F5F8AE780D6B1" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_75F49B4D886DEE404CE75F8AE780115E" xlink:to="loc_hsc_HarscoIndustrialMember_4997F4F9E0F0ED27C62F5F8AE780D6B1" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoRailMember" xlink:label="loc_hsc_HarscoRailMember_A36F1F2FD67AE78F88175F8AE7811743" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_75F49B4D886DEE404CE75F8AE780115E" xlink:to="loc_hsc_HarscoRailMember_A36F1F2FD67AE78F88175F8AE7811743" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_527921D2C6487A1098BE5F8AE7812416" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:to="loc_us-gaap_Revenues_527921D2C6487A1098BE5F8AE7812416" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_80997086DF911AAC42575F8AE781F050" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:to="loc_us-gaap_OperatingIncomeLoss_80997086DF911AAC42575F8AE781F050" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_0D2FB7164322AC2B700B5F8AE781CDD9" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:to="loc_us-gaap_Assets_0D2FB7164322AC2B700B5F8AE781CDD9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_51DC7F08EB7C56C6B4605F8AE781D3B8" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_51DC7F08EB7C56C6B4605F8AE781D3B8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquireProductiveAssets" xlink:label="loc_us-gaap_PaymentsToAcquireProductiveAssets_08D14DDFCE943FF369205F8AE7811833" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:to="loc_us-gaap_PaymentsToAcquireProductiveAssets_08D14DDFCE943FF369205F8AE7811833" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest_8E5CC9F02D99A5EC503F5F8AE7814EC3" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:to="loc_us-gaap_InvestmentIncomeInterest_8E5CC9F02D99A5EC503F5F8AE7814EC3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_CF494E7DC4B3006343585F8AE7810A79" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:to="loc_us-gaap_InterestExpense_CF494E7DC4B3006343585F8AE7810A79" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionExpenseReversalOfExpenseNoncash" xlink:label="loc_us-gaap_PensionExpenseReversalOfExpenseNoncash_6C518AEB0426FB33C7205F8AE7814B1C" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:to="loc_us-gaap_PensionExpenseReversalOfExpenseNoncash_6C518AEB0426FB33C7205F8AE7814B1C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_9B30BD12104FFDDF3D025F8AE783E23E" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_9B30BD12104FFDDF3D025F8AE783E23E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_6E644D86B54E18E862625F8AE7831BF1" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_2D6976A7D4FCEFAE03C95F8AE781094D" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_6E644D86B54E18E862625F8AE7831BF1" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/InformationBySegmentAndGeographicAreaDetails4" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems" xlink:label="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_0260C9442CA03A6F3EE8453E95642EDD" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable" xlink:label="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_483A999196684D75DACB453E9564721B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_0260C9442CA03A6F3EE8453E95642EDD" xlink:to="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_483A999196684D75DACB453E9564721B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsAxis" xlink:label="loc_srt_ConsolidationItemsAxis_E25ECD0DD512BF692C72453E9564DA5F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_483A999196684D75DACB453E9564721B" xlink:to="loc_srt_ConsolidationItemsAxis_E25ECD0DD512BF692C72453E9564DA5F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsDomain" xlink:label="loc_srt_ConsolidationItemsDomain_F050E5763AE2354D5565453E9564058A_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_E25ECD0DD512BF692C72453E9564DA5F" xlink:to="loc_srt_ConsolidationItemsDomain_F050E5763AE2354D5565453E9564058A_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsDomain" xlink:label="loc_srt_ConsolidationItemsDomain_F050E5763AE2354D5565453E9564058A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_E25ECD0DD512BF692C72453E9564DA5F" xlink:to="loc_srt_ConsolidationItemsDomain_F050E5763AE2354D5565453E9564058A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CorporateNonSegmentMember" xlink:label="loc_us-gaap_CorporateNonSegmentMember_CFC974F3F4EDECA2241D453E9564FA03" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_F050E5763AE2354D5565453E9564058A" xlink:to="loc_us-gaap_CorporateNonSegmentMember_CFC974F3F4EDECA2241D453E9564FA03" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis_0341CBDCBAE518AED33F453E95647593" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_483A999196684D75DACB453E9564721B" xlink:to="loc_srt_ProductOrServiceAxis_0341CBDCBAE518AED33F453E95647593" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_5764EBABF468DA63477A453E9564642B_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_0341CBDCBAE518AED33F453E95647593" xlink:to="loc_srt_ProductsAndServicesDomain_5764EBABF468DA63477A453E9564642B_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_5764EBABF468DA63477A453E9564642B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_0341CBDCBAE518AED33F453E95647593" xlink:to="loc_srt_ProductsAndServicesDomain_5764EBABF468DA63477A453E9564642B" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AirCooledHeatExchangersMember" xlink:label="loc_hsc_AirCooledHeatExchangersMember_A84365D1EC7565EAB008453E95647E8D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_5764EBABF468DA63477A453E9564642B" xlink:to="loc_hsc_AirCooledHeatExchangersMember_A84365D1EC7565EAB008453E95647E8D" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/InformationBySegmentAndGeographicAreaTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/Leases" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/LeasesNarrativeDetails" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/LeasesScheduleOfFutureLeaseMaturitiesDetails" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/LeasesScheduleOfFutureMinimumPaymentsDetails" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/LeasesSupplementalBalanceSheetInformationDetails" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/LeasesSupplementalCashFlowInformationDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_8EB56F0C77B8D6465B243AE2FBF72C34" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_C794574EEF4B068604C93AE2FBF68929" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_8EB56F0C77B8D6465B243AE2FBF72C34" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_C794574EEF4B068604C93AE2FBF68929" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_CBA9C2D18B8DD30624FC3AE2FBF66A9F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_C794574EEF4B068604C93AE2FBF68929" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_CBA9C2D18B8DD30624FC3AE2FBF66A9F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_A725618F4E36250C5B973AE2FBF7DE5C_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_CBA9C2D18B8DD30624FC3AE2FBF66A9F" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_A725618F4E36250C5B973AE2FBF7DE5C_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_A725618F4E36250C5B973AE2FBF7DE5C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_CBA9C2D18B8DD30624FC3AE2FBF66A9F" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_A725618F4E36250C5B973AE2FBF7DE5C" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_D87EAACFE1BAD5610B6B3AE2FBF7311C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_A725618F4E36250C5B973AE2FBF7DE5C" xlink:to="loc_hsc_CleanEarthMember_D87EAACFE1BAD5610B6B3AE2FBF7311C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasePayments" xlink:label="loc_us-gaap_OperatingLeasePayments_64BA7E75E0760DD313173AE2FBF81AB7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_8EB56F0C77B8D6465B243AE2FBF72C34" xlink:to="loc_us-gaap_OperatingLeasePayments_64BA7E75E0760DD313173AE2FBF81AB7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FinanceLeaseInterestPaymentOnLiability" xlink:label="loc_us-gaap_FinanceLeaseInterestPaymentOnLiability_07997C8BA769B7211AD03AE2FBF8EC40" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_8EB56F0C77B8D6465B243AE2FBF72C34" xlink:to="loc_us-gaap_FinanceLeaseInterestPaymentOnLiability_07997C8BA769B7211AD03AE2FBF8EC40" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_B7367C9CD2C0CA3C92D33AE2FBF873F8" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_8EB56F0C77B8D6465B243AE2FBF72C34" xlink:to="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_B7367C9CD2C0CA3C92D33AE2FBF873F8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_8B41F7952CA5C71A3F443AE2FBF82513" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_8EB56F0C77B8D6465B243AE2FBF72C34" xlink:to="loc_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_8B41F7952CA5C71A3F443AE2FBF82513" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/LeasesSupplementalIncomeStatementInformationDetails" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/LeasesSupplementalLeaseInformationDetails" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/LeasesTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/OtherExpenses" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/OtherExpensesDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_52BEFCDAD414A6EADBA95F8AE6D5CF83" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_4D4D8A5BFF7DB6C3F15C5F8AE6D14C8C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_52BEFCDAD414A6EADBA95F8AE6D5CF83" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_4D4D8A5BFF7DB6C3F15C5F8AE6D14C8C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_7CB34B719F258FDF58D55F8AE6D1F66A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_4D4D8A5BFF7DB6C3F15C5F8AE6D14C8C" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_7CB34B719F258FDF58D55F8AE6D1F66A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_4F4D7ED8AD30BCBBDA245F8AE6D1B585_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7CB34B719F258FDF58D55F8AE6D1F66A" xlink:to="loc_us-gaap_SegmentDomain_4F4D7ED8AD30BCBBDA245F8AE6D1B585_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_4F4D7ED8AD30BCBBDA245F8AE6D1B585" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7CB34B719F258FDF58D55F8AE6D1F66A" xlink:to="loc_us-gaap_SegmentDomain_4F4D7ED8AD30BCBBDA245F8AE6D1B585" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoMetalsAndMineralsMember" xlink:label="loc_hsc_HarscoMetalsAndMineralsMember_C41B16A5990F0519DB5D5F8AE6D1007E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_4F4D7ED8AD30BCBBDA245F8AE6D1B585" xlink:to="loc_hsc_HarscoMetalsAndMineralsMember_C41B16A5990F0519DB5D5F8AE6D1007E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_29E97FFAADBE6418DCDB5F8AE6D1D3A0" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_4F4D7ED8AD30BCBBDA245F8AE6D1B585" xlink:to="loc_hsc_CleanEarthMember_29E97FFAADBE6418DCDB5F8AE6D1D3A0" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoIndustrialMember" xlink:label="loc_hsc_HarscoIndustrialMember_AEDA3A54FD1C78817A8D5F8AE6D18858" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_4F4D7ED8AD30BCBBDA245F8AE6D1B585" xlink:to="loc_hsc_HarscoIndustrialMember_AEDA3A54FD1C78817A8D5F8AE6D18858" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoRailMember" xlink:label="loc_hsc_HarscoRailMember_3CDD3AFF8423A0AC9BE15F8AE6D1F55C" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_4F4D7ED8AD30BCBBDA245F8AE6D1B585" xlink:to="loc_hsc_HarscoRailMember_3CDD3AFF8423A0AC9BE15F8AE6D1F55C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MaterialReconcilingItemsMember" xlink:label="loc_us-gaap_MaterialReconcilingItemsMember_C693004031BE1CBFEFB45F8AE6D19B06" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_4F4D7ED8AD30BCBBDA245F8AE6D1B585" xlink:to="loc_us-gaap_MaterialReconcilingItemsMember_C693004031BE1CBFEFB45F8AE6D19B06" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoEnvironmentalSegmentMember" xlink:label="loc_hsc_HarscoEnvironmentalSegmentMember_670B38AB444C4B143A3A5F8AE6D1E9F8" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_4F4D7ED8AD30BCBBDA245F8AE6D1B585" xlink:to="loc_hsc_HarscoEnvironmentalSegmentMember_670B38AB444C4B143A3A5F8AE6D1E9F8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainLossOnDispositionOfAssets" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets_F40E18BF9B366B580D2F5F8AE6D5CD99" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_52BEFCDAD414A6EADBA95F8AE6D5CF83" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets_F40E18BF9B366B580D2F5F8AE6D5CD99" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SeveranceCosts1" xlink:label="loc_us-gaap_SeveranceCosts1_F27CCD7CC542948326165F8AE6D55A08" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_52BEFCDAD414A6EADBA95F8AE6D5CF83" xlink:to="loc_us-gaap_SeveranceCosts1_F27CCD7CC542948326165F8AE6D55A08" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_BusinessExitCostsExcludingSeverance" xlink:label="loc_hsc_BusinessExitCostsExcludingSeverance_60421E65CD224873EFFC5F8AE6D56A72" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_52BEFCDAD414A6EADBA95F8AE6D5CF83" xlink:to="loc_hsc_BusinessExitCostsExcludingSeverance_60421E65CD224873EFFC5F8AE6D56A72" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetImpairmentCharges" xlink:label="loc_us-gaap_AssetImpairmentCharges_C72A04E1E408E9E5AEC45F8AE6D5F1ED" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_52BEFCDAD414A6EADBA95F8AE6D5CF83" xlink:to="loc_us-gaap_AssetImpairmentCharges_C72A04E1E408E9E5AEC45F8AE6D5F1ED" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationAsset1" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationAsset1_3FB3C9E2360A78FC64FC5F8AE6D5ABAA" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_52BEFCDAD414A6EADBA95F8AE6D5CF83" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationAsset1_3FB3C9E2360A78FC64FC5F8AE6D5ABAA" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_OtherMiscellaneousIncomeExpense" xlink:label="loc_hsc_OtherMiscellaneousIncomeExpense_E2B2A648E9F0B8771A595F8AE6D6D128" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_52BEFCDAD414A6EADBA95F8AE6D5CF83" xlink:to="loc_hsc_OtherMiscellaneousIncomeExpense_E2B2A648E9F0B8771A595F8AE6D6D128" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_IncomeExpenseOtherNet" xlink:label="loc_hsc_IncomeExpenseOtherNet_4D0727EB2A446B41816B5F8AE6D6559A" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_52BEFCDAD414A6EADBA95F8AE6D5CF83" xlink:to="loc_hsc_IncomeExpenseOtherNet_4D0727EB2A446B41816B5F8AE6D6559A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_6C1CFFD5B1CCF7736FB75F8AE6D616D8" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_52BEFCDAD414A6EADBA95F8AE6D5CF83" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_6C1CFFD5B1CCF7736FB75F8AE6D616D8" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/OtherExpensesTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/PropertyPlantAndEquipment" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/PropertyPlantAndEquipmentDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_BFD67B7BE83F28565C6A54C5790C341D" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_E1516E05EE39388E7DB254C5790C0D7D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_BFD67B7BE83F28565C6A54C5790C341D" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_E1516E05EE39388E7DB254C5790C0D7D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_88DAFB3F389719352ED054C5790C70EC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_E1516E05EE39388E7DB254C5790C0D7D" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_88DAFB3F389719352ED054C5790C70EC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_AF775780014ADB11A25754C5790CA15A_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_88DAFB3F389719352ED054C5790C70EC" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_AF775780014ADB11A25754C5790CA15A_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_AF775780014ADB11A25754C5790CA15A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_88DAFB3F389719352ED054C5790C70EC" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_AF775780014ADB11A25754C5790CA15A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LandMember" xlink:label="loc_us-gaap_LandMember_90F4DCF375D968AB169354C5790C3ACC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_AF775780014ADB11A25754C5790CA15A" xlink:to="loc_us-gaap_LandMember_90F4DCF375D968AB169354C5790C3ACC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LandImprovementsMember" xlink:label="loc_us-gaap_LandImprovementsMember_34D5460A39F0A75AC10F54C5790C6F36" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_AF775780014ADB11A25754C5790CA15A" xlink:to="loc_us-gaap_LandImprovementsMember_34D5460A39F0A75AC10F54C5790C6F36" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_D21D26723F0F02F1630554C5790C635B" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_AF775780014ADB11A25754C5790CA15A" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_D21D26723F0F02F1630554C5790C635B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MachineryAndEquipmentMember" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_860A7A8F8F18868A6DF654C5790C9DED" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_AF775780014ADB11A25754C5790CA15A" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_860A7A8F8F18868A6DF654C5790C9DED" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConstructionInProgressMember" xlink:label="loc_us-gaap_ConstructionInProgressMember_0DCB797F42F80063EE7B54C5790CB646" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_AF775780014ADB11A25754C5790CA15A" xlink:to="loc_us-gaap_ConstructionInProgressMember_0DCB797F42F80063EE7B54C5790CB646" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_2AB25D79AA6D3764AC8E54C5790C4036" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_E1516E05EE39388E7DB254C5790C0D7D" xlink:to="loc_srt_RangeAxis_2AB25D79AA6D3764AC8E54C5790C4036" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_CCCF2A79467C783E634654C5790CE87A_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_2AB25D79AA6D3764AC8E54C5790C4036" xlink:to="loc_srt_RangeMember_CCCF2A79467C783E634654C5790CE87A_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_CCCF2A79467C783E634654C5790CE87A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_2AB25D79AA6D3764AC8E54C5790C4036" xlink:to="loc_srt_RangeMember_CCCF2A79467C783E634654C5790CE87A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_3ADC5FB421D8448531BD54C5790CA662" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_CCCF2A79467C783E634654C5790CE87A" xlink:to="loc_srt_MinimumMember_3ADC5FB421D8448531BD54C5790CA662" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_10AD16E9A56A07A8308254C5790CEEAE" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_CCCF2A79467C783E634654C5790CE87A" xlink:to="loc_srt_MaximumMember_10AD16E9A56A07A8308254C5790CEEAE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_13683F020A615CC0827654C5790CE098" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_BFD67B7BE83F28565C6A54C5790C341D" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_13683F020A615CC0827654C5790CE098" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_A366530D1A002614DC7E54C5790C50ED" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_BFD67B7BE83F28565C6A54C5790C341D" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_A366530D1A002614DC7E54C5790C50ED" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_49A4B9F26E23D00C04E454C5790CC2DC" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_BFD67B7BE83F28565C6A54C5790C341D" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_49A4B9F26E23D00C04E454C5790CC2DC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_BB436CCD4405A06EBF4854C5790C9E91" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_BFD67B7BE83F28565C6A54C5790C341D" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_BB436CCD4405A06EBF4854C5790C9E91" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/PropertyPlantAndEquipmentTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/RecentlyAdoptedAndRecentlyIssuedAccountingStandards" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/RecentlyAdoptedAndRecentlyIssuedAccountingStandardsNarrativeDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_71E398BFA543997E6A8E5F8AEB60C997" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_EED7F4696065BA5737D55F8AEB5E590A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_71E398BFA543997E6A8E5F8AEB60C997" xlink:to="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_EED7F4696065BA5737D55F8AEB5E590A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_B6049004903D80E5C2B95F8AEB5ED152" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_EED7F4696065BA5737D55F8AEB5E590A" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_B6049004903D80E5C2B95F8AEB5ED152" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_9939AA85FF56E5DA71DB5F8AEB5E3E73_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_B6049004903D80E5C2B95F8AEB5ED152" xlink:to="loc_us-gaap_EquityComponentDomain_9939AA85FF56E5DA71DB5F8AEB5E3E73_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_9939AA85FF56E5DA71DB5F8AEB5E3E73" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_B6049004903D80E5C2B95F8AEB5ED152" xlink:to="loc_us-gaap_EquityComponentDomain_9939AA85FF56E5DA71DB5F8AEB5E3E73" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_6D10F6C025CF7F5711CC5F8AEB5ECF2B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_9939AA85FF56E5DA71DB5F8AEB5E3E73" xlink:to="loc_us-gaap_RetainedEarningsMember_6D10F6C025CF7F5711CC5F8AEB5ECF2B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_CE9DD22F82E9F8474BAA5F8AEB601AD7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_71E398BFA543997E6A8E5F8AEB60C997" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_CE9DD22F82E9F8474BAA5F8AEB601AD7" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_StrandedIncomeTaxEffectsinAccumulatedOtherComprehensiveIncome" xlink:label="loc_hsc_StrandedIncomeTaxEffectsinAccumulatedOtherComprehensiveIncome_2DFC780BAF2F55847F515F8AEB61BE89" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_71E398BFA543997E6A8E5F8AEB60C997" xlink:to="loc_hsc_StrandedIncomeTaxEffectsinAccumulatedOtherComprehensiveIncome_2DFC780BAF2F55847F515F8AEB61BE89" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:label="loc_us-gaap_OperatingLeaseLiability_6166883D64FC5CDCA1455F8AEB615499" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_71E398BFA543997E6A8E5F8AEB60C997" xlink:to="loc_us-gaap_OperatingLeaseLiability_6166883D64FC5CDCA1455F8AEB615499" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/RecentlyAdoptedAndRecentlyIssuedAccountingStandardsTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/RevenueRecognition" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/RevenueRecognitionNarrativeDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_B60842D4D76928CE88B55F8AE71BAC1C" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_9E9F0484DE966F79BBCD5F8AE71775D3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_B60842D4D76928CE88B55F8AE71BAC1C" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_9E9F0484DE966F79BBCD5F8AE71775D3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsAxis" xlink:label="loc_srt_ConsolidationItemsAxis_57144A909DC2343FDA155F8AE71731AB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_9E9F0484DE966F79BBCD5F8AE71775D3" xlink:to="loc_srt_ConsolidationItemsAxis_57144A909DC2343FDA155F8AE71731AB" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsDomain" xlink:label="loc_srt_ConsolidationItemsDomain_4DDB962C9766D37D087E5F8AE7176575_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_57144A909DC2343FDA155F8AE71731AB" xlink:to="loc_srt_ConsolidationItemsDomain_4DDB962C9766D37D087E5F8AE7176575_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsDomain" xlink:label="loc_srt_ConsolidationItemsDomain_4DDB962C9766D37D087E5F8AE7176575" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_57144A909DC2343FDA155F8AE71731AB" xlink:to="loc_srt_ConsolidationItemsDomain_4DDB962C9766D37D087E5F8AE7176575" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:label="loc_us-gaap_OperatingSegmentsMember_717D8EF0510D48A1BD655F8AE717FAC8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_4DDB962C9766D37D087E5F8AE7176575" xlink:to="loc_us-gaap_OperatingSegmentsMember_717D8EF0510D48A1BD655F8AE717FAC8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CorporateNonSegmentMember" xlink:label="loc_us-gaap_CorporateNonSegmentMember_2BEAAF1A45958A1CDCF15F8AE717A96A" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_4DDB962C9766D37D087E5F8AE7176575" xlink:to="loc_us-gaap_CorporateNonSegmentMember_2BEAAF1A45958A1CDCF15F8AE717A96A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis_205CA2B7D28B4BC785225F8AE717D194" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_9E9F0484DE966F79BBCD5F8AE71775D3" xlink:to="loc_srt_ProductOrServiceAxis_205CA2B7D28B4BC785225F8AE717D194" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_205CA2B7D28B4BC785225F8AE717D194" xlink:to="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_205CA2B7D28B4BC785225F8AE717D194" xlink:to="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_WasteProcessingandReuseSolutionsDomain" xlink:label="loc_hsc_WasteProcessingandReuseSolutionsDomain_F237531138A8DCC31DB55F8AE71726A0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8" xlink:to="loc_hsc_WasteProcessingandReuseSolutionsDomain_F237531138A8DCC31DB55F8AE71726A0" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_RailwayContractingServicesDomain" xlink:label="loc_hsc_RailwayContractingServicesDomain_A32E54EA10C3E464B1AB5F8AE717FA93" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8" xlink:to="loc_hsc_RailwayContractingServicesDomain_A32E54EA10C3E464B1AB5F8AE717FA93" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AftermarketPartsandServicesSafetyandDiagnosticTechnologyDomain" xlink:label="loc_hsc_AftermarketPartsandServicesSafetyandDiagnosticTechnologyDomain_B8431B7F127143A9B4B05F8AE7171449" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8" xlink:to="loc_hsc_AftermarketPartsandServicesSafetyandDiagnosticTechnologyDomain_B8431B7F127143A9B4B05F8AE7171449" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AluminumDrossandScrapProcessingSystemsDomain" xlink:label="loc_hsc_AluminumDrossandScrapProcessingSystemsDomain_C72E990E665C28CF23565F8AE717AB89" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8" xlink:to="loc_hsc_AluminumDrossandScrapProcessingSystemsDomain_C72E990E665C28CF23565F8AE717AB89" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_RailwayTrackMaintenanceEquipmentDomain" xlink:label="loc_hsc_RailwayTrackMaintenanceEquipmentDomain_5CDC89027F54FA0E71C35F8AE71B8A5A" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8" xlink:to="loc_hsc_RailwayTrackMaintenanceEquipmentDomain_5CDC89027F54FA0E71C35F8AE71B8A5A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ProductsAndServicesGeneralCorporateMember" xlink:label="loc_hsc_ProductsAndServicesGeneralCorporateMember_5F04138F5A6B1C72E8DB5F8AE71BE1D7" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8" xlink:to="loc_hsc_ProductsAndServicesGeneralCorporateMember_5F04138F5A6B1C72E8DB5F8AE71BE1D7" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ProductsAndServicesOnsiteServicesAndMaterialLogisticsProductQualityImprovementAndResourceRecoveryMember" xlink:label="loc_hsc_ProductsAndServicesOnsiteServicesAndMaterialLogisticsProductQualityImprovementAndResourceRecoveryMember_4355E4058FE7244445525F8AE71BDA4E" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8" xlink:to="loc_hsc_ProductsAndServicesOnsiteServicesAndMaterialLogisticsProductQualityImprovementAndResourceRecoveryMember_4355E4058FE7244445525F8AE71BDA4E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AppliedProductsDomain" xlink:label="loc_hsc_AppliedProductsDomain_3571775EA4A53050C98B5F8AE71BFF6A" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_44323DAE13B81A1985BC5F8AE7174EB8" xlink:to="loc_hsc_AppliedProductsDomain_3571775EA4A53050C98B5F8AE71BFF6A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_5CEA7D16F55005133DFF5F8AE71B23F8" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_9E9F0484DE966F79BBCD5F8AE71775D3" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_5CEA7D16F55005133DFF5F8AE71B23F8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_0F231BA0813C44AD32465F8AE71B4774_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_5CEA7D16F55005133DFF5F8AE71B23F8" xlink:to="loc_us-gaap_SegmentDomain_0F231BA0813C44AD32465F8AE71B4774_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_0F231BA0813C44AD32465F8AE71B4774" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_5CEA7D16F55005133DFF5F8AE71B23F8" xlink:to="loc_us-gaap_SegmentDomain_0F231BA0813C44AD32465F8AE71B4774" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoMetalsAndMineralsMember" xlink:label="loc_hsc_HarscoMetalsAndMineralsMember_4486E02B5934E93477CA5F8AE71B6D81" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0F231BA0813C44AD32465F8AE71B4774" xlink:to="loc_hsc_HarscoMetalsAndMineralsMember_4486E02B5934E93477CA5F8AE71B6D81" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_87FC19CDB0532F546B665F8AE71BB467" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0F231BA0813C44AD32465F8AE71B4774" xlink:to="loc_hsc_CleanEarthMember_87FC19CDB0532F546B665F8AE71BB467" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoRailMember" xlink:label="loc_hsc_HarscoRailMember_9AC086448FC232E26F6B5F8AE71BFA22" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0F231BA0813C44AD32465F8AE71B4774" xlink:to="loc_hsc_HarscoRailMember_9AC086448FC232E26F6B5F8AE71BFA22" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoEnvironmentalSegmentMember" xlink:label="loc_hsc_HarscoEnvironmentalSegmentMember_28040327824D604646F05F8AE71BC355" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0F231BA0813C44AD32465F8AE71B4774" xlink:to="loc_hsc_HarscoEnvironmentalSegmentMember_28040327824D604646F05F8AE71BC355" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_6834049847C8C56CB8405F8AE71BB755" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_9E9F0484DE966F79BBCD5F8AE71775D3" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_6834049847C8C56CB8405F8AE71BB755" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_0F1FB949EAD7CBB502875F8AE71B760B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_B60842D4D76928CE88B55F8AE71BAC1C" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_0F1FB949EAD7CBB502875F8AE71B760B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_4938425FF6F17CAAF9835F8AE72022AA" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_B60842D4D76928CE88B55F8AE71BAC1C" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_4938425FF6F17CAAF9835F8AE72022AA" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/RevenueRecognitionPerformanceObligationPeriodNarrativeDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_5A1C7607B35B4540266C39F1018A18C4" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_FC4E901D7A60938C2A6139F10188B3CA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_5A1C7607B35B4540266C39F1018A18C4" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_FC4E901D7A60938C2A6139F10188B3CA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_9CF95CCBEB8C75F62E8A39F101884163" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_FC4E901D7A60938C2A6139F10188B3CA" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_9CF95CCBEB8C75F62E8A39F101884163" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_B076FD1F0E6D337A2DAF39F10188F465_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9CF95CCBEB8C75F62E8A39F101884163" xlink:to="loc_us-gaap_SegmentDomain_B076FD1F0E6D337A2DAF39F10188F465_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_B076FD1F0E6D337A2DAF39F10188F465" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9CF95CCBEB8C75F62E8A39F101884163" xlink:to="loc_us-gaap_SegmentDomain_B076FD1F0E6D337A2DAF39F10188F465" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoMetalsAndMineralsMember" xlink:label="loc_hsc_HarscoMetalsAndMineralsMember_F4C245E2B87C90E342CF39F1018906D4" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_B076FD1F0E6D337A2DAF39F10188F465" xlink:to="loc_hsc_HarscoMetalsAndMineralsMember_F4C245E2B87C90E342CF39F1018906D4" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoRailMember" xlink:label="loc_hsc_HarscoRailMember_CC1D10648E2B82214D5539F10189F938" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_B076FD1F0E6D337A2DAF39F10188F465" xlink:to="loc_hsc_HarscoRailMember_CC1D10648E2B82214D5539F10189F938" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_9433AFC6858CFF470B1039F1018A96F8" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_FC4E901D7A60938C2A6139F10188B3CA" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_9433AFC6858CFF470B1039F1018A96F8" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_A078933047E8DDD693DC39F1018A6B2C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_5A1C7607B35B4540266C39F1018A18C4" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_A078933047E8DDD693DC39F1018A6B2C" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/RevenueRecognitionSummaryOfRevenuesByPrimaryGeographicalMarketsDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_3073BC130492332A957B5F8AE7456558" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_9C20AEE3BB97CCE5D2CF5F8AE739F62D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3073BC130492332A957B5F8AE7456558" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_9C20AEE3BB97CCE5D2CF5F8AE739F62D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_3B7AC69211703D7F439B5F8AE73954E0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_9C20AEE3BB97CCE5D2CF5F8AE739F62D" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_3B7AC69211703D7F439B5F8AE73954E0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_8BD8C5C3C501236310055F8AE739AC1C_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3B7AC69211703D7F439B5F8AE73954E0" xlink:to="loc_us-gaap_SegmentDomain_8BD8C5C3C501236310055F8AE739AC1C_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_8BD8C5C3C501236310055F8AE739AC1C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3B7AC69211703D7F439B5F8AE73954E0" xlink:to="loc_us-gaap_SegmentDomain_8BD8C5C3C501236310055F8AE739AC1C" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoEnvironmentalSegmentMember" xlink:label="loc_hsc_HarscoEnvironmentalSegmentMember_CC3B100F1B549B5D38B55F8AE739E5A9" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8BD8C5C3C501236310055F8AE739AC1C" xlink:to="loc_hsc_HarscoEnvironmentalSegmentMember_CC3B100F1B549B5D38B55F8AE739E5A9" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CleanEarthMember" xlink:label="loc_hsc_CleanEarthMember_284568465D09E22EBBA65F8AE7399D77" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8BD8C5C3C501236310055F8AE739AC1C" xlink:to="loc_hsc_CleanEarthMember_284568465D09E22EBBA65F8AE7399D77" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoMetalsAndMineralsMember" xlink:label="loc_hsc_HarscoMetalsAndMineralsMember_DDDE40ACF62AC3F259D15F8AE74196EB" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8BD8C5C3C501236310055F8AE739AC1C" xlink:to="loc_hsc_HarscoMetalsAndMineralsMember_DDDE40ACF62AC3F259D15F8AE74196EB" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_HarscoRailMember" xlink:label="loc_hsc_HarscoRailMember_CD2ACABDF0D18320032F5F8AE74119E7" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8BD8C5C3C501236310055F8AE739AC1C" xlink:to="loc_hsc_HarscoRailMember_CD2ACABDF0D18320032F5F8AE74119E7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsAxis" xlink:label="loc_srt_ConsolidationItemsAxis_18237DAD35A63AB153575F8AE741A3CF" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_9C20AEE3BB97CCE5D2CF5F8AE739F62D" xlink:to="loc_srt_ConsolidationItemsAxis_18237DAD35A63AB153575F8AE741A3CF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsDomain" xlink:label="loc_srt_ConsolidationItemsDomain_18E3B657EDF0DCC8D1CA5F8AE741C31E_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_18237DAD35A63AB153575F8AE741A3CF" xlink:to="loc_srt_ConsolidationItemsDomain_18E3B657EDF0DCC8D1CA5F8AE741C31E_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ConsolidationItemsDomain" xlink:label="loc_srt_ConsolidationItemsDomain_18E3B657EDF0DCC8D1CA5F8AE741C31E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_18237DAD35A63AB153575F8AE741A3CF" xlink:to="loc_srt_ConsolidationItemsDomain_18E3B657EDF0DCC8D1CA5F8AE741C31E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:label="loc_us-gaap_OperatingSegmentsMember_BAB79EC697B275D2CE565F8AE74159F7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_18E3B657EDF0DCC8D1CA5F8AE741C31E" xlink:to="loc_us-gaap_OperatingSegmentsMember_BAB79EC697B275D2CE565F8AE74159F7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CorporateNonSegmentMember" xlink:label="loc_us-gaap_CorporateNonSegmentMember_F5DF250A7B047FE352FB5F8AE7418377" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_18E3B657EDF0DCC8D1CA5F8AE741C31E" xlink:to="loc_us-gaap_CorporateNonSegmentMember_F5DF250A7B047FE352FB5F8AE7418377" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="loc_srt_StatementGeographicalAxis_94ED7FA00C397B1B8AAF5F8AE7414A27" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_9C20AEE3BB97CCE5D2CF5F8AE739F62D" xlink:to="loc_srt_StatementGeographicalAxis_94ED7FA00C397B1B8AAF5F8AE7414A27" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_2B2AF629663ACE5E31B35F8AE7416E4A_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_94ED7FA00C397B1B8AAF5F8AE7414A27" xlink:to="loc_srt_SegmentGeographicalDomain_2B2AF629663ACE5E31B35F8AE7416E4A_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srt_SegmentGeographicalDomain_2B2AF629663ACE5E31B35F8AE7416E4A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_94ED7FA00C397B1B8AAF5F8AE7414A27" xlink:to="loc_srt_SegmentGeographicalDomain_2B2AF629663ACE5E31B35F8AE7416E4A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_NorthAmericaMember" xlink:label="loc_srt_NorthAmericaMember_EC13A60F280D71A123BD5F8AE74198EA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_2B2AF629663ACE5E31B35F8AE7416E4A" xlink:to="loc_srt_NorthAmericaMember_EC13A60F280D71A123BD5F8AE74198EA" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_WesternEuropeMember" xlink:label="loc_hsc_WesternEuropeMember_8560068C64EE31592BB85F8AE7412320" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_2B2AF629663ACE5E31B35F8AE7416E4A" xlink:to="loc_hsc_WesternEuropeMember_8560068C64EE31592BB85F8AE7412320" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_LatinAmericaMember" xlink:label="loc_srt_LatinAmericaMember_6707DDC9F4D333E600885F8AE74105AF" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_2B2AF629663ACE5E31B35F8AE7416E4A" xlink:to="loc_srt_LatinAmericaMember_6707DDC9F4D333E600885F8AE74105AF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_AsiaPacificMember" xlink:label="loc_srt_AsiaPacificMember_C23B64CA6AE8C326FCAB5F8AE741B1A1" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_2B2AF629663ACE5E31B35F8AE7416E4A" xlink:to="loc_srt_AsiaPacificMember_C23B64CA6AE8C326FCAB5F8AE741B1A1" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_MiddleEastAndAfricaMember" xlink:label="loc_hsc_MiddleEastAndAfricaMember_5D607B27693D7803583E5F8AE741F9EE" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_2B2AF629663ACE5E31B35F8AE7416E4A" xlink:to="loc_hsc_MiddleEastAndAfricaMember_5D607B27693D7803583E5F8AE741F9EE" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_EasternEuropeMember" xlink:label="loc_hsc_EasternEuropeMember_B96458DFF6B80D030B9B5F8AE74127F0" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_2B2AF629663ACE5E31B35F8AE7416E4A" xlink:to="loc_hsc_EasternEuropeMember_B96458DFF6B80D030B9B5F8AE74127F0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis_301303D6E4F347285CD25F8AE745AA27" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_9C20AEE3BB97CCE5D2CF5F8AE739F62D" xlink:to="loc_srt_ProductOrServiceAxis_301303D6E4F347285CD25F8AE745AA27" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_301303D6E4F347285CD25F8AE745AA27" xlink:to="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_301303D6E4F347285CD25F8AE745AA27" xlink:to="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ProductsAndServicesOnsiteServicesAndMaterialLogisticsProductQualityImprovementAndResourceRecoveryMember" xlink:label="loc_hsc_ProductsAndServicesOnsiteServicesAndMaterialLogisticsProductQualityImprovementAndResourceRecoveryMember_CC1B56FD07D6D11D671B5F8AE74516FA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F" xlink:to="loc_hsc_ProductsAndServicesOnsiteServicesAndMaterialLogisticsProductQualityImprovementAndResourceRecoveryMember_CC1B56FD07D6D11D671B5F8AE74516FA" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AppliedProductsDomain" xlink:label="loc_hsc_AppliedProductsDomain_9FBD304C89AD8BA3381D5F8AE745FB69" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F" xlink:to="loc_hsc_AppliedProductsDomain_9FBD304C89AD8BA3381D5F8AE745FB69" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AluminumDrossandScrapProcessingSystemsDomain" xlink:label="loc_hsc_AluminumDrossandScrapProcessingSystemsDomain_FC2D822EA9B42762EB265F8AE745C1F0" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F" xlink:to="loc_hsc_AluminumDrossandScrapProcessingSystemsDomain_FC2D822EA9B42762EB265F8AE745C1F0" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_RailwayTrackMaintenanceEquipmentDomain" xlink:label="loc_hsc_RailwayTrackMaintenanceEquipmentDomain_C2B2E0201D2C14F5198D5F8AE7450BAE" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F" xlink:to="loc_hsc_RailwayTrackMaintenanceEquipmentDomain_C2B2E0201D2C14F5198D5F8AE7450BAE" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_AftermarketPartsandServicesSafetyandDiagnosticTechnologyDomain" xlink:label="loc_hsc_AftermarketPartsandServicesSafetyandDiagnosticTechnologyDomain_17A6E6ED2A6FF8089A5D5F8AE74580D2" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F" xlink:to="loc_hsc_AftermarketPartsandServicesSafetyandDiagnosticTechnologyDomain_17A6E6ED2A6FF8089A5D5F8AE74580D2" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_RailwayContractingServicesDomain" xlink:label="loc_hsc_RailwayContractingServicesDomain_E266B5816D92805AD0635F8AE7456286" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F" xlink:to="loc_hsc_RailwayContractingServicesDomain_E266B5816D92805AD0635F8AE7456286" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_WasteProcessingandReuseSolutionsDomain" xlink:label="loc_hsc_WasteProcessingandReuseSolutionsDomain_49D224857EB3C4DB21335F8AE745F33A" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F" xlink:to="loc_hsc_WasteProcessingandReuseSolutionsDomain_49D224857EB3C4DB21335F8AE745F33A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ProductsAndServicesGeneralCorporateMember" xlink:label="loc_hsc_ProductsAndServicesGeneralCorporateMember_CD17C22A6D428DCAE9155F8AE74520D2" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_49DFFDE7D433BFFE24B05F8AE7458F7F" xlink:to="loc_hsc_ProductsAndServicesGeneralCorporateMember_CD17C22A6D428DCAE9155F8AE74520D2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_0C4998E24A5587AF7C2D5F8AE745D9FC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3073BC130492332A957B5F8AE7456558" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_0C4998E24A5587AF7C2D5F8AE745D9FC" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/RevenueRecognitionTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/ScheduleIiValuationAndQualifyingAccounts" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/ScheduleIiValuationAndQualifyingAccountsDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ValuationAndQualifyingAccountsDisclosureLineItems" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_7DCD332242221B6772094454BFE4FA6C" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ValuationAndQualifyingAccountsDisclosureTable" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_8BBBC43296308A05E6874454BFE49CBE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_7DCD332242221B6772094454BFE4FA6C" xlink:to="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_8BBBC43296308A05E6874454BFE49CBE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowanceByDeferredTaxAssetAxis" xlink:label="loc_us-gaap_ValuationAllowanceByDeferredTaxAssetAxis_7979CB5C627FC5C61FF54454BFE44CDA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_8BBBC43296308A05E6874454BFE49CBE" xlink:to="loc_us-gaap_ValuationAllowanceByDeferredTaxAssetAxis_7979CB5C627FC5C61FF54454BFE44CDA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetDomain" xlink:label="loc_us-gaap_DeferredTaxAssetDomain_5188C74B1B1986B544E54454BFE48B6A_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowanceByDeferredTaxAssetAxis_7979CB5C627FC5C61FF54454BFE44CDA" xlink:to="loc_us-gaap_DeferredTaxAssetDomain_5188C74B1B1986B544E54454BFE48B6A_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetDomain" xlink:label="loc_us-gaap_DeferredTaxAssetDomain_5188C74B1B1986B544E54454BFE48B6A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowanceByDeferredTaxAssetAxis_7979CB5C627FC5C61FF54454BFE44CDA" xlink:to="loc_us-gaap_DeferredTaxAssetDomain_5188C74B1B1986B544E54454BFE48B6A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ValuationAllowanceDeferredTaxAssetliquidationandMergerofEntitiesMember" xlink:label="loc_hsc_ValuationAllowanceDeferredTaxAssetliquidationandMergerofEntitiesMember_A890D1BEF15F16F6B35B445DC9F0173D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredTaxAssetDomain_5188C74B1B1986B544E54454BFE48B6A" xlink:to="loc_hsc_ValuationAllowanceDeferredTaxAssetliquidationandMergerofEntitiesMember_A890D1BEF15F16F6B35B445DC9F0173D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ChangeInAccountingMethodAccountedForAsChangeInEstimateMember" xlink:label="loc_us-gaap_ChangeInAccountingMethodAccountedForAsChangeInEstimateMember_7C19E0821314A55E051E4454BFE491E9" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredTaxAssetDomain_5188C74B1B1986B544E54454BFE48B6A" xlink:to="loc_us-gaap_ChangeInAccountingMethodAccountedForAsChangeInEstimateMember_7C19E0821314A55E051E4454BFE491E9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalLossCarryforwardMember" xlink:label="loc_us-gaap_CapitalLossCarryforwardMember_DB8938890BCC3EE661354454BFE40561" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredTaxAssetDomain_5188C74B1B1986B544E54454BFE48B6A" xlink:to="loc_us-gaap_CapitalLossCarryforwardMember_DB8938890BCC3EE661354454BFE40561" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ValuationAllowanceDeferredTaxAssetPensionAdjustmentsMember" xlink:label="loc_hsc_ValuationAllowanceDeferredTaxAssetPensionAdjustmentsMember_2EEB86B11750DCCF0AB54454BFE4A54D" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredTaxAssetDomain_5188C74B1B1986B544E54454BFE48B6A" xlink:to="loc_hsc_ValuationAllowanceDeferredTaxAssetPensionAdjustmentsMember_2EEB86B11750DCCF0AB54454BFE4A54D" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ValuationAllowanceDeferredTaxAssetTaxCreditMember" xlink:label="loc_hsc_ValuationAllowanceDeferredTaxAssetTaxCreditMember_6F89B8465C6C2EC84B8F445F33BFBBC0" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredTaxAssetDomain_5188C74B1B1986B544E54454BFE48B6A" xlink:to="loc_hsc_ValuationAllowanceDeferredTaxAssetTaxCreditMember_6F89B8465C6C2EC84B8F445F33BFBBC0" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_UStaxratechangesMemberMember" xlink:label="loc_hsc_UStaxratechangesMemberMember_EE7E5286D4F85AF21DB64454BFE40273" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredTaxAssetDomain_5188C74B1B1986B544E54454BFE48B6A" xlink:to="loc_hsc_UStaxratechangesMemberMember_EE7E5286D4F85AF21DB64454BFE40273" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_E1376DA37F31E6BFA4324454BFE4F2B7" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_8BBBC43296308A05E6874454BFE49CBE" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_E1376DA37F31E6BFA4324454BFE4F2B7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_3EE89AA4E7260EF755344454BFE4CD28_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_E1376DA37F31E6BFA4324454BFE4F2B7" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_3EE89AA4E7260EF755344454BFE4CD28_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_3EE89AA4E7260EF755344454BFE4CD28" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_E1376DA37F31E6BFA4324454BFE4F2B7" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_3EE89AA4E7260EF755344454BFE4CD28" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ChangeInAccountingMethodAccountedForAsChangeInEstimateMember" xlink:label="loc_us-gaap_ChangeInAccountingMethodAccountedForAsChangeInEstimateMember_D8DEF7DCA0F909306233445818C484BC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_3EE89AA4E7260EF755344454BFE4CD28" xlink:to="loc_us-gaap_ChangeInAccountingMethodAccountedForAsChangeInEstimateMember_D8DEF7DCA0F909306233445818C484BC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllowanceForCreditLossMember" xlink:label="loc_us-gaap_AllowanceForCreditLossMember_11EE2488D855B1339FBF4454BFE41A93" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_3EE89AA4E7260EF755344454BFE4CD28" xlink:to="loc_us-gaap_AllowanceForCreditLossMember_11EE2488D855B1339FBF4454BFE41A93" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember" xlink:label="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_BA0B9A1C938095CC49D64454BFE43E19" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_3EE89AA4E7260EF755344454BFE4CD28" xlink:to="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_BA0B9A1C938095CC49D64454BFE43E19" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MovementInValuationAllowancesAndReservesRollForward" xlink:label="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_FAFC3B8A462265B1D6154454BFE4CA37" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_7DCD332242221B6772094454BFE4FA6C" xlink:to="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_FAFC3B8A462265B1D6154454BFE4CA37" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowancesAndReservesBalance" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_4CDB0D6ACF46A4C9D2664454BFE473B6" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_FAFC3B8A462265B1D6154454BFE4CA37" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesBalance_4CDB0D6ACF46A4C9D2664454BFE473B6" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_FA14A039D130ED5E90B34454BFE43932" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_FAFC3B8A462265B1D6154454BFE4CA37" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_FA14A039D130ED5E90B34454BFE43932" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowancesAndReservesAdjustments" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesAdjustments_41D1B2C24956F9829A734454BFE4D3C7" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_FAFC3B8A462265B1D6154454BFE4CA37" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesAdjustments_41D1B2C24956F9829A734454BFE4D3C7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_CD5A1ED5B339EFCD9C4C4454BFE4AA89" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_FAFC3B8A462265B1D6154454BFE4CA37" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_CD5A1ED5B339EFCD9C4C4454BFE4AA89" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:label="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_BDC32569BA1BC3D9BE1B4454BFE4E84C" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_7DCD332242221B6772094454BFE4FA6C" xlink:to="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_BDC32569BA1BC3D9BE1B4454BFE4E84C" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/StockBasedCompensation" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/StockBasedCompensationPerformanceStockUnitsDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C854BE551CB29BEA1BE844E5A5F9D8D2" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_71BD13183D621FE3DAF944E5A5F935FA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C854BE551CB29BEA1BE844E5A5F9D8D2" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_71BD13183D621FE3DAF944E5A5F935FA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_D632B39A529D0F4517FF44E5A5F929A5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_71BD13183D621FE3DAF944E5A5F935FA" xlink:to="loc_us-gaap_AwardTypeAxis_D632B39A529D0F4517FF44E5A5F929A5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E0F77E5FB5BE98B7BE5544E5A5F967D2_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_D632B39A529D0F4517FF44E5A5F929A5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E0F77E5FB5BE98B7BE5544E5A5F967D2_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E0F77E5FB5BE98B7BE5544E5A5F967D2" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_D632B39A529D0F4517FF44E5A5F929A5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E0F77E5FB5BE98B7BE5544E5A5F967D2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="loc_us-gaap_PerformanceSharesMember_0615B8AD5B599472561444E5A5F981D2" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E0F77E5FB5BE98B7BE5544E5A5F967D2" xlink:to="loc_us-gaap_PerformanceSharesMember_0615B8AD5B599472561444E5A5F981D2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_EE73C00FFBB594311D5844E5A5F975CF" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_71BD13183D621FE3DAF944E5A5F935FA" xlink:to="loc_srt_RangeAxis_EE73C00FFBB594311D5844E5A5F975CF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_7CF1437256992BC99FDD44E5A5F9F238_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_EE73C00FFBB594311D5844E5A5F975CF" xlink:to="loc_srt_RangeMember_7CF1437256992BC99FDD44E5A5F9F238_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_7CF1437256992BC99FDD44E5A5F9F238" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_EE73C00FFBB594311D5844E5A5F975CF" xlink:to="loc_srt_RangeMember_7CF1437256992BC99FDD44E5A5F9F238" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_F8A0DE3EA3399ADB88DE44E5A5F92F7F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_7CF1437256992BC99FDD44E5A5F9F238" xlink:to="loc_srt_MinimumMember_F8A0DE3EA3399ADB88DE44E5A5F92F7F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_D598AB39D8F5B9594AB944E5A5F99A32" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_7CF1437256992BC99FDD44E5A5F9F238" xlink:to="loc_srt_MaximumMember_D598AB39D8F5B9594AB944E5A5F99A32" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod" xlink:label="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod_410067EA79034BDCC83444E5A5F9C522" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C854BE551CB29BEA1BE844E5A5F9D8D2" xlink:to="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod_410067EA79034BDCC83444E5A5F9C522" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceStockPayoutPercentageOfInitialGrant" xlink:label="loc_hsc_ShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceStockPayoutPercentageOfInitialGrant_53A82D22B13634B697A944E5A5F9265D" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C854BE551CB29BEA1BE844E5A5F9D8D2" xlink:to="loc_hsc_ShareBasedCompensationArrangementsByShareBasedPaymentAwardPerformanceStockPayoutPercentageOfInitialGrant_53A82D22B13634B697A944E5A5F9265D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A93F432926687682F46D44E5A5F97C13" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C854BE551CB29BEA1BE844E5A5F9D8D2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A93F432926687682F46D44E5A5F97C13" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_57E06A1091155A74263544E5A5F9EC76" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A93F432926687682F46D44E5A5F97C13" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_57E06A1091155A74263544E5A5F9EC76" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_8308A56520CB4E614D0F44E5A5F9168D" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A93F432926687682F46D44E5A5F97C13" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_8308A56520CB4E614D0F44E5A5F9168D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_640E28CE9B68CA222CEF44E5A5F91FAD" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A93F432926687682F46D44E5A5F97C13" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_640E28CE9B68CA222CEF44E5A5F91FAD" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate_1F426A679BEC659D380744E5A5F9C51D" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A93F432926687682F46D44E5A5F97C13" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate_1F426A679BEC659D380744E5A5F9C51D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_3D02DB1D22DE5783C9F344E5A5F95895" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_A93F432926687682F46D44E5A5F97C13" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_3D02DB1D22DE5783C9F344E5A5F95895" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_333C6E42BA9A6D96064C44E5A5F9B37E" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C854BE551CB29BEA1BE844E5A5F9D8D2" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_333C6E42BA9A6D96064C44E5A5F9B37E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_45736EE06A3AA4FB809D44E5A5F95A30" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C854BE551CB29BEA1BE844E5A5F9D8D2" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_45736EE06A3AA4FB809D44E5A5F95A30" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_6D13EC2C97FB84B90B3644E5A5F93EB3" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C854BE551CB29BEA1BE844E5A5F9D8D2" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_6D13EC2C97FB84B90B3644E5A5F93EB3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7F10DB57BB3F2EF1042E44E5A5F96719" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C854BE551CB29BEA1BE844E5A5F9D8D2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7F10DB57BB3F2EF1042E44E5A5F96719" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_C6BFF77648B7628A540244E5A5F9CF89" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7F10DB57BB3F2EF1042E44E5A5F96719" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_C6BFF77648B7628A540244E5A5F9CF89" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_834E2996CF5571B55BAD44E5A5F96125" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7F10DB57BB3F2EF1042E44E5A5F96719" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_834E2996CF5571B55BAD44E5A5F96125" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_2AA5324FAB163CB7107544E5A5F9026A" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7F10DB57BB3F2EF1042E44E5A5F96719" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_2AA5324FAB163CB7107544E5A5F9026A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures_D76B5565CDB39303426244E5A5F9CF99" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_7F10DB57BB3F2EF1042E44E5A5F96719" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures_D76B5565CDB39303426244E5A5F9CF99" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A24C1E902BAB22CAD4A644E5A5F903E6" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C854BE551CB29BEA1BE844E5A5F9D8D2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A24C1E902BAB22CAD4A644E5A5F903E6" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_728D95D440837501137144E5A5F9975F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A24C1E902BAB22CAD4A644E5A5F903E6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_728D95D440837501137144E5A5F9975F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_7797523638BD5EE4B28D44E5A5F9F53D" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A24C1E902BAB22CAD4A644E5A5F903E6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_7797523638BD5EE4B28D44E5A5F9F53D" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SharebasedCompensationArrangementbySharebasedPaymentawaryNonOptionEquityInstrumentsCancellations" xlink:label="loc_hsc_SharebasedCompensationArrangementbySharebasedPaymentawaryNonOptionEquityInstrumentsCancellations_87FE0FA275F7171A5A6F44F926AB4F2B" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A24C1E902BAB22CAD4A644E5A5F903E6" xlink:to="loc_hsc_SharebasedCompensationArrangementbySharebasedPaymentawaryNonOptionEquityInstrumentsCancellations_87FE0FA275F7171A5A6F44F926AB4F2B" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCancellationsWeightedAverageGrantDateFairValue" xlink:label="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCancellationsWeightedAverageGrantDateFairValue_9D39434FEA5CA9D3617B44E5A5F9060E" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A24C1E902BAB22CAD4A644E5A5F903E6" xlink:to="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCancellationsWeightedAverageGrantDateFairValue_9D39434FEA5CA9D3617B44E5A5F9060E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_26D21AE433F8492D020E44E5A5F94E1F" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C854BE551CB29BEA1BE844E5A5F9D8D2" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_26D21AE433F8492D020E44E5A5F94E1F" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/StockBasedCompensationRestrictedStockDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3D6F55887F96A42CD359453E960B6AD8" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3D6F55887F96A42CD359453E960B6AD8" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_DD379AB03F69EA7E66AB453E960BF254" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3D6F55887F96A42CD359453E960B6AD8" xlink:to="loc_us-gaap_PlanNameAxis_DD379AB03F69EA7E66AB453E960BF254" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_B1B81BCC710591FA8E69453E960BAEDA_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_DD379AB03F69EA7E66AB453E960BF254" xlink:to="loc_us-gaap_PlanNameDomain_B1B81BCC710591FA8E69453E960BAEDA_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_B1B81BCC710591FA8E69453E960BAEDA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_DD379AB03F69EA7E66AB453E960BF254" xlink:to="loc_us-gaap_PlanNameDomain_B1B81BCC710591FA8E69453E960BAEDA" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_EquityAndIncentiveCompensationPlan2013Member" xlink:label="loc_hsc_EquityAndIncentiveCompensationPlan2013Member_647EE0B11FC5EFD46E62453E960B6B2A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_B1B81BCC710591FA8E69453E960BAEDA" xlink:to="loc_hsc_EquityAndIncentiveCompensationPlan2013Member_647EE0B11FC5EFD46E62453E960B6B2A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_NonEmployeeDirectorsStockPlan1995Member" xlink:label="loc_hsc_NonEmployeeDirectorsStockPlan1995Member_F20BA7F88273B2D0A852453E960BE7EE" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_B1B81BCC710591FA8E69453E960BAEDA" xlink:to="loc_hsc_NonEmployeeDirectorsStockPlan1995Member_F20BA7F88273B2D0A852453E960BE7EE" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ExecutiveIncentiveCompensationPlan1995Member" xlink:label="loc_hsc_ExecutiveIncentiveCompensationPlan1995Member_68EF528EFAC1897D69D8453E960BA639" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_B1B81BCC710591FA8E69453E960BAEDA" xlink:to="loc_hsc_ExecutiveIncentiveCompensationPlan1995Member_68EF528EFAC1897D69D8453E960BA639" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_F88B2D8EDA1616292F81453E960BE05F" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3D6F55887F96A42CD359453E960B6AD8" xlink:to="loc_us-gaap_AwardTypeAxis_F88B2D8EDA1616292F81453E960BE05F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B256B7A88AF27A9F448D453E960BF3EC_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_F88B2D8EDA1616292F81453E960BE05F" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B256B7A88AF27A9F448D453E960BF3EC_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B256B7A88AF27A9F448D453E960BF3EC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_F88B2D8EDA1616292F81453E960BE05F" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B256B7A88AF27A9F448D453E960BF3EC" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_EquityAwardsOtherThanOptionsAndStockAppreciationRightsMember" xlink:label="loc_hsc_EquityAwardsOtherThanOptionsAndStockAppreciationRightsMember_B64CE08B3F26DF2049EA453E960B441E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B256B7A88AF27A9F448D453E960BF3EC" xlink:to="loc_hsc_EquityAwardsOtherThanOptionsAndStockAppreciationRightsMember_B64CE08B3F26DF2049EA453E960B441E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_AED6AFCB7D739AED2DF4453E960B2B03" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B256B7A88AF27A9F448D453E960BF3EC" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_AED6AFCB7D739AED2DF4453E960B2B03" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardDateAxis" xlink:label="loc_us-gaap_AwardDateAxis_FBFB3DDBB92DB205990C453E960B43A9" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3D6F55887F96A42CD359453E960B6AD8" xlink:to="loc_us-gaap_AwardDateAxis_FBFB3DDBB92DB205990C453E960B43A9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardDateDomain" xlink:label="loc_us-gaap_AwardDateDomain_9E9FA07300C649AE7263453E960B456B_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardDateAxis_FBFB3DDBB92DB205990C453E960B43A9" xlink:to="loc_us-gaap_AwardDateDomain_9E9FA07300C649AE7263453E960B456B_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardDateDomain" xlink:label="loc_us-gaap_AwardDateDomain_9E9FA07300C649AE7263453E960B456B" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardDateAxis_FBFB3DDBB92DB205990C453E960B43A9" xlink:to="loc_us-gaap_AwardDateDomain_9E9FA07300C649AE7263453E960B456B" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_IssuePeriodThreeMember" xlink:label="loc_hsc_IssuePeriodThreeMember_6088D62F8E1008DF03AE453E960B4F10" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_9E9FA07300C649AE7263453E960B456B" xlink:to="loc_hsc_IssuePeriodThreeMember_6088D62F8E1008DF03AE453E960B4F10" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_IssuePeriodFourMember" xlink:label="loc_hsc_IssuePeriodFourMember_C58FC036D21627E7D2BC453E960B0D6A" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_9E9FA07300C649AE7263453E960B456B" xlink:to="loc_hsc_IssuePeriodFourMember_C58FC036D21627E7D2BC453E960B0D6A" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_IssuePeriodFiveMember" xlink:label="loc_hsc_IssuePeriodFiveMember_0D7D769D05582C4904C5453E960B63CF" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_9E9FA07300C649AE7263453E960B456B" xlink:to="loc_hsc_IssuePeriodFiveMember_0D7D769D05582C4904C5453E960B63CF" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_IssuePeriodSixMember" xlink:label="loc_hsc_IssuePeriodSixMember_B85DA1B9EF7729288C45453E960BC112" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_9E9FA07300C649AE7263453E960B456B" xlink:to="loc_hsc_IssuePeriodSixMember_B85DA1B9EF7729288C45453E960BC112" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_IssuePeriodSevenMemberDomain" xlink:label="loc_hsc_IssuePeriodSevenMemberDomain_0346D944D91EC0071CB7453E960B0AB7" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_9E9FA07300C649AE7263453E960B456B" xlink:to="loc_hsc_IssuePeriodSevenMemberDomain_0346D944D91EC0071CB7453E960B0AB7" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_IssuePeriodEightDomain" xlink:label="loc_hsc_IssuePeriodEightDomain_A7E369BF4F798AB9E3FF453E960BBC87" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_9E9FA07300C649AE7263453E960B456B" xlink:to="loc_hsc_IssuePeriodEightDomain_A7E369BF4F798AB9E3FF453E960BBC87" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_0E55F6F4F044F1E733F7453E960B5049" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_0E55F6F4F044F1E733F7453E960B5049" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_0ED474B029BACA11DBCA453E960BD473" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_0ED474B029BACA11DBCA453E960BD473" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_E507F3DE0888A72143E3453E960B4F3B" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_E507F3DE0888A72143E3453E960B4F3B" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_3F79AB8DFD418549BF13453E960BE4CC" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_3F79AB8DFD418549BF13453E960BE4CC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_EA6C977A276AEF99100B453E960B15B4" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_EA6C977A276AEF99100B453E960B15B4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_27C374C6AA090088CFB4453E960BE09C" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_27C374C6AA090088CFB4453E960BE09C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_94B2754402DA7AD1E784453E960B00EE" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_94B2754402DA7AD1E784453E960B00EE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_D1AD8B94AB4A74C4BAD8453E960BD481" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_D1AD8B94AB4A74C4BAD8453E960BD481" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_DE6401EB7D5321C0C0B7453E960B758F" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_DE6401EB7D5321C0C0B7453E960B758F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_2BAB98DBDFE7E6E795E5453E960BA437" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_DE6401EB7D5321C0C0B7453E960B758F" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_2BAB98DBDFE7E6E795E5453E960BA437" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_F14A25BCB08162D86FB5453E960B2B2A" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_DE6401EB7D5321C0C0B7453E960B758F" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_F14A25BCB08162D86FB5453E960B2B2A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_6CE88B4DA8298D92D858453E960BC986" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_DE6401EB7D5321C0C0B7453E960B758F" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_6CE88B4DA8298D92D858453E960BC986" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_2E82E563C44093C8C24D453E960BC11F" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_2E82E563C44093C8C24D453E960BC11F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_BAABA4254FE69266E381453E961B64CA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_2E82E563C44093C8C24D453E960BC11F" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_BAABA4254FE69266E381453E961B64CA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_0D1EE6FC5BE75F160274453E961CD0AC" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_2E82E563C44093C8C24D453E960BC11F" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_0D1EE6FC5BE75F160274453E961CD0AC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_AA48E74229B161E3750B453E961CDADF" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_2E82E563C44093C8C24D453E960BC11F" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_AA48E74229B161E3750B453E961CDADF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract_E3D5CE4E82540C67DE9F453E961CF254" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract_E3D5CE4E82540C67DE9F453E961CF254" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_1BB49D1F72B11436FA4D453E961C1659" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract_E3D5CE4E82540C67DE9F453E961CF254" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_1BB49D1F72B11436FA4D453E961C1659" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_BA9B6C178674E8CB4C1F453E961CC4D9" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract_E3D5CE4E82540C67DE9F453E961CF254" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_BA9B6C178674E8CB4C1F453E961CC4D9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet" xlink:label="loc_us-gaap_AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet_4BB047CF571052F87BC6453E961C9CEA" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B4E4FCBC8AD3D08E9D0B453E960BB120" xlink:to="loc_us-gaap_AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet_4BB047CF571052F87BC6453E961C9CEA" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/StockBasedCompensationStockAppreciationRightsDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_53E3E48EBDE0AC90A623453E95E91F17" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_53E3E48EBDE0AC90A623453E95E91F17" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_1AD03D1EA5806BDBC432453E95E90BC5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_53E3E48EBDE0AC90A623453E95E91F17" xlink:to="loc_us-gaap_PlanNameAxis_1AD03D1EA5806BDBC432453E95E90BC5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_C09F1593B3CC7CC52244453E95F9AEC5_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_1AD03D1EA5806BDBC432453E95E90BC5" xlink:to="loc_us-gaap_PlanNameDomain_C09F1593B3CC7CC52244453E95F9AEC5_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_C09F1593B3CC7CC52244453E95F9AEC5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_1AD03D1EA5806BDBC432453E95E90BC5" xlink:to="loc_us-gaap_PlanNameDomain_C09F1593B3CC7CC52244453E95F9AEC5" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ExecutiveIncentiveCompensationPlan1995Member" xlink:label="loc_hsc_ExecutiveIncentiveCompensationPlan1995Member_F1765AD59717E9860948453E95F98333" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_C09F1593B3CC7CC52244453E95F9AEC5" xlink:to="loc_hsc_ExecutiveIncentiveCompensationPlan1995Member_F1765AD59717E9860948453E95F98333" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_EquityAndIncentiveCompensationPlan2013Member" xlink:label="loc_hsc_EquityAndIncentiveCompensationPlan2013Member_DA6EAAD6E67194F1BC04453E95FA7C9D" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_C09F1593B3CC7CC52244453E95F9AEC5" xlink:to="loc_hsc_EquityAndIncentiveCompensationPlan2013Member_DA6EAAD6E67194F1BC04453E95FA7C9D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_4D2C719CB3D9AD7CDC09453E95FA4AA6" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_53E3E48EBDE0AC90A623453E95E91F17" xlink:to="loc_us-gaap_AwardTypeAxis_4D2C719CB3D9AD7CDC09453E95FA4AA6" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3395AE463A5BAC1B38FA453E95FA4196_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_4D2C719CB3D9AD7CDC09453E95FA4AA6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3395AE463A5BAC1B38FA453E95FA4196_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3395AE463A5BAC1B38FA453E95FA4196" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_4D2C719CB3D9AD7CDC09453E95FA4AA6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3395AE463A5BAC1B38FA453E95FA4196" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_431D5189E706B1DA4702453E95FA2266" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3395AE463A5BAC1B38FA453E95FA4196" xlink:to="loc_us-gaap_EmployeeStockOptionMember_431D5189E706B1DA4702453E95FA2266" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockAppreciationRightsSARSMember" xlink:label="loc_us-gaap_StockAppreciationRightsSARSMember_F1E827B958B536B06C9B453E95FA88CF" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3395AE463A5BAC1B38FA453E95FA4196" xlink:to="loc_us-gaap_StockAppreciationRightsSARSMember_F1E827B958B536B06C9B453E95FA88CF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_DB941563AF67EE772A40453E95FA9601" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_53E3E48EBDE0AC90A623453E95E91F17" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_DB941563AF67EE772A40453E95FA9601" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_E0F3A3F003ACBA1C66C3453E95FA9C61_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_DB941563AF67EE772A40453E95FA9601" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_E0F3A3F003ACBA1C66C3453E95FA9C61_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_E0F3A3F003ACBA1C66C3453E95FA9C61" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_DB941563AF67EE772A40453E95FA9601" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_E0F3A3F003ACBA1C66C3453E95FA9C61" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ExercisePriceRangeFourMember" xlink:label="loc_hsc_ExercisePriceRangeFourMember_B30A24408CC293D294DA453E95FA59C6" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_E0F3A3F003ACBA1C66C3453E95FA9C61" xlink:to="loc_hsc_ExercisePriceRangeFourMember_B30A24408CC293D294DA453E95FA59C6" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ExercisePriceRangeFiveMember" xlink:label="loc_hsc_ExercisePriceRangeFiveMember_91319EBD70C14BF6A560453E95FA12B6" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_E0F3A3F003ACBA1C66C3453E95FA9C61" xlink:to="loc_hsc_ExercisePriceRangeFiveMember_91319EBD70C14BF6A560453E95FA12B6" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ExercisePriceRangeSixMember" xlink:label="loc_hsc_ExercisePriceRangeSixMember_3331BCF1CFB51BEE1280453E95FA5EE0" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_E0F3A3F003ACBA1C66C3453E95FA9C61" xlink:to="loc_hsc_ExercisePriceRangeSixMember_3331BCF1CFB51BEE1280453E95FA5EE0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_CC7A889B2B2F2003A33A453E95FAB5F5" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_53E3E48EBDE0AC90A623453E95E91F17" xlink:to="loc_srt_RangeAxis_CC7A889B2B2F2003A33A453E95FAB5F5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_D0C31B82824EE48B370D453E95FAC4D9_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_CC7A889B2B2F2003A33A453E95FAB5F5" xlink:to="loc_srt_RangeMember_D0C31B82824EE48B370D453E95FAC4D9_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_D0C31B82824EE48B370D453E95FAC4D9" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_CC7A889B2B2F2003A33A453E95FAB5F5" xlink:to="loc_srt_RangeMember_D0C31B82824EE48B370D453E95FAC4D9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_59444FDA1237F5213A87453E95FAC61C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_D0C31B82824EE48B370D453E95FAC4D9" xlink:to="loc_srt_MinimumMember_59444FDA1237F5213A87453E95FAC61C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_0F23D236BF59AB9ADD23453E95FA4FEF" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_D0C31B82824EE48B370D453E95FAC4D9" xlink:to="loc_srt_MaximumMember_0F23D236BF59AB9ADD23453E95FA4FEF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_05C55250902F9DA8F653453E95FA98D0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_05C55250902F9DA8F653453E95FA98D0" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsExercisedinPeriodWeightedAverageExercisePrice" xlink:label="loc_hsc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsExercisedinPeriodWeightedAverageExercisePrice_5BA9634C09B74282F040453E95FA39E0" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_hsc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsExercisedinPeriodWeightedAverageExercisePrice_5BA9634C09B74282F040453E95FA39E0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_CA4A84D7767AD17BE19C453E95FAFAAC" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_CA4A84D7767AD17BE19C453E95FAFAAC" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_9E7ACAC39254147589C3453E95FA9B40" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_9E7ACAC39254147589C3453E95FA9B40" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_9F9DCD66A21452B90A90453E95FA13F0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_9E7ACAC39254147589C3453E95FA9B40" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_9F9DCD66A21452B90A90453E95FA13F0" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_757C3171F95275494ED3453E95FAB77C" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_9E7ACAC39254147589C3453E95FA9B40" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_757C3171F95275494ED3453E95FAB77C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_E9FBAD31D95E7AB972E9453E95FAA7B5" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_9E7ACAC39254147589C3453E95FA9B40" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_E9FBAD31D95E7AB972E9453E95FAA7B5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_F67333722AC812538631453E95FAD774" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_9E7ACAC39254147589C3453E95FA9B40" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_F67333722AC812538631453E95FAD774" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharePrice" xlink:label="loc_us-gaap_SharePrice_C987209330B89024F84F453E95FABE10" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_9E7ACAC39254147589C3453E95FA9B40" xlink:to="loc_us-gaap_SharePrice_C987209330B89024F84F453E95FABE10" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_0D069D8585F9E736EF2D453E95FA4312" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_0D069D8585F9E736EF2D453E95FA4312" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_879C76FBA2A344D503E4453E95FA9BC7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_0D069D8585F9E736EF2D453E95FA4312" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_879C76FBA2A344D503E4453E95FA9BC7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_6988883E27DE331BDB40453E95FA6D6A" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_0D069D8585F9E736EF2D453E95FA4312" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_6988883E27DE331BDB40453E95FA6D6A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised_197074A495CBF81D4643453E95FA18E3" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_0D069D8585F9E736EF2D453E95FA4312" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised_197074A495CBF81D4643453E95FA18E3" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures_9D090782D47FD23B3D9F453E95FAD12F" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_0D069D8585F9E736EF2D453E95FA4312" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures_9D090782D47FD23B3D9F453E95FAD12F" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageExercisePriceRollForward" xlink:label="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageExercisePriceRollForward_4E4FDAF0F407368747D6453E95FABA70" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageExercisePriceRollForward_4E4FDAF0F407368747D6453E95FABA70" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageExercisePrice" xlink:label="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageExercisePrice_2118EF24CD9E19B1DA64453E95FA42DD" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageExercisePriceRollForward_4E4FDAF0F407368747D6453E95FABA70" xlink:to="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageExercisePrice_2118EF24CD9E19B1DA64453E95FA42DD" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageExercisePrice_18BD0DD23E40C2DD31DF453E95FAAA03" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageExercisePriceRollForward_4E4FDAF0F407368747D6453E95FABA70" xlink:to="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageExercisePrice_18BD0DD23E40C2DD31DF453E95FAAA03" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriodWeightedAverageExercisePrice" xlink:label="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriodWeightedAverageExercisePrice_D1F4D29497415590D63D453E95FAC117" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageExercisePriceRollForward_4E4FDAF0F407368747D6453E95FABA70" xlink:to="loc_hsc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriodWeightedAverageExercisePrice_D1F4D29497415590D63D453E95FAC117" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_0ACCE54F045162C6FD20453E95FABCF2" xlink:type="locator"/>
<link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_0ACCE54F045162C6FD20453E95FABCF2" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateIntrinsicValueExercised" xlink:label="loc_hsc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateIntrinsicValueExercised_66B73EE209C19AA380FB453E95FA726A" xlink:type="locator"/>
<link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_hsc_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateIntrinsicValueExercised_66B73EE209C19AA380FB453E95FA726A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_19C9761F5875628C9C1B453E95FA5A84" xlink:type="locator"/>
<link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_19C9761F5875628C9C1B453E95FA5A84" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_CC8F0838BF1B3FC7A102453E95FA11B7" xlink:type="locator"/>
<link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_CC8F0838BF1B3FC7A102453E95FA11B7" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SharebasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeNumberOfVestedShares" xlink:label="loc_hsc_SharebasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeNumberOfVestedShares_A4CFD0F50D66BDB8E274453E95FAD890" xlink:type="locator"/>
<link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_hsc_SharebasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeNumberOfVestedShares_A4CFD0F50D66BDB8E274453E95FAD890" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SharebasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeNumberOfUnvestedShares" xlink:label="loc_hsc_SharebasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeNumberOfUnvestedShares_2734F26AD10EDD2964AE453E95FA1950" xlink:type="locator"/>
<link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_hsc_SharebasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeNumberOfUnvestedShares_2734F26AD10EDD2964AE453E95FA1950" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeOutstandingSARsWeightedAverageExercisePrice" xlink:label="loc_hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeOutstandingSARsWeightedAverageExercisePrice_B88641492145D3F1E4B3453E95FAEE2E" xlink:type="locator"/>
<link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeOutstandingSARsWeightedAverageExercisePrice_B88641492145D3F1E4B3453E95FAEE2E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeOutstandingSARsWeightedAverageRemainingContractualTerm" xlink:label="loc_hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeOutstandingSARsWeightedAverageRemainingContractualTerm_D848531F763DB37832BC453E95FA7B4E" xlink:type="locator"/>
<link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeOutstandingSARsWeightedAverageRemainingContractualTerm_D848531F763DB37832BC453E95FA7B4E" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeNumberOfExercisableShares" xlink:label="loc_hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeNumberOfExercisableShares_BF6A50148665404D136B453E95FAC072" xlink:type="locator"/>
<link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeNumberOfExercisableShares_BF6A50148665404D136B453E95FAC072" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeExercisableSARsWeightedAverageExercisePrice" xlink:label="loc_hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeExercisableSARsWeightedAverageExercisePrice_154A80E8E41D81767AEF453E95FAB8A5" xlink:type="locator"/>
<link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_hsc_ShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsExercisePriceRangeExercisableSARsWeightedAverageExercisePrice_154A80E8E41D81767AEF453E95FAB8A5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_CEB116A692338B1F84FB453E95FA6FD4" xlink:type="locator"/>
<link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_CEB116A692338B1F84FB453E95FA6FD4" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_B9C3E9D50DA17845CA1D453E95FA4919" xlink:type="locator"/>
<link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_B9C3E9D50DA17845CA1D453E95FA4919" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_8BDBF27A14050EAA2517453E95FAC381" xlink:type="locator"/>
<link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_8BDBF27A14050EAA2517453E95FAC381" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_D08858234354A4EFFB50453E95FAEF57" xlink:type="locator"/>
<link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_D08858234354A4EFFB50453E95FAEF57" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_BD204E5B90BB38A3A7E2453E95FA55CE" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_D08858234354A4EFFB50453E95FAEF57" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_BD204E5B90BB38A3A7E2453E95FA55CE" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_0235014F55E5E7A6E4CC453E95FA9D3D" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_D08858234354A4EFFB50453E95FAEF57" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_0235014F55E5E7A6E4CC453E95FA9D3D" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_B8CFD41684D7AE5036FD453E95FA803E" xlink:type="locator"/>
<link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_B8CFD41684D7AE5036FD453E95FA803E" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_0A04906C447200C40DE9453E95FAF208" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_B8CFD41684D7AE5036FD453E95FA803E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_0A04906C447200C40DE9453E95FAF208" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_5DFCB2826C710B627F5E453E95FA6AEF" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_B8CFD41684D7AE5036FD453E95FA803E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_5DFCB2826C710B627F5E453E95FA6AEF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_87D5093FAE46E7BA7A16453E95FA7509" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_B8CFD41684D7AE5036FD453E95FA803E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_87D5093FAE46E7BA7A16453E95FA7509" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_56DEC3DA856158C2E189453E95FA571A" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_B8CFD41684D7AE5036FD453E95FA803E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_56DEC3DA856158C2E189453E95FA571A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_8E9AD5BD690D60A0E884453E95FADC55" xlink:type="locator"/>
<link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_8E9AD5BD690D60A0E884453E95FADC55" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_43E5E90BB89FBE3579CD453E95FA4E40" xlink:type="locator"/>
<link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_43E5E90BB89FBE3579CD453E95FA4E40" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_6B46CFCEE94C3D86C749453E95FA1283" xlink:type="locator"/>
<link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_6B46CFCEE94C3D86C749453E95FA1283" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_F01D33B7019568162206453E95FA735C" xlink:type="locator"/>
<link:definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_849596DBF65D13CFB204453E95FAB67D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_F01D33B7019568162206453E95FA735C" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/StockBasedCompensationStockOptionsDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C9B8A58F463C9B9784B954C575D09D7D" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_CF00E5BCF6CB6AB17D4A54C575D041AB" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C9B8A58F463C9B9784B954C575D09D7D" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_CF00E5BCF6CB6AB17D4A54C575D041AB" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_FCBBCA74F675F892E25054C575D0498C" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_CF00E5BCF6CB6AB17D4A54C575D041AB" xlink:to="loc_us-gaap_AwardTypeAxis_FCBBCA74F675F892E25054C575D0498C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B7FECF90631DDEB3F71D54C575D020D5_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_FCBBCA74F675F892E25054C575D0498C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B7FECF90631DDEB3F71D54C575D020D5_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B7FECF90631DDEB3F71D54C575D020D5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_FCBBCA74F675F892E25054C575D0498C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B7FECF90631DDEB3F71D54C575D020D5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_99539F03E1B8290A269954C575D0DB23" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_B7FECF90631DDEB3F71D54C575D020D5" xlink:to="loc_us-gaap_EmployeeStockOptionMember_99539F03E1B8290A269954C575D0DB23" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_8FEF47B3547789912BF854C575D00C9C" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_CF00E5BCF6CB6AB17D4A54C575D041AB" xlink:to="loc_srt_RangeAxis_8FEF47B3547789912BF854C575D00C9C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_010447985C2F4103BC6B54C575D08741_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_8FEF47B3547789912BF854C575D00C9C" xlink:to="loc_srt_RangeMember_010447985C2F4103BC6B54C575D08741_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_010447985C2F4103BC6B54C575D08741" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_8FEF47B3547789912BF854C575D00C9C" xlink:to="loc_srt_RangeMember_010447985C2F4103BC6B54C575D08741" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_66CD57B0A34E2C66ABBF54C575D09450" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_010447985C2F4103BC6B54C575D08741" xlink:to="loc_srt_MaximumMember_66CD57B0A34E2C66ABBF54C575D09450" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_C8A88889E3CDD766E86D54C575D0169A" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C9B8A58F463C9B9784B954C575D09D7D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_C8A88889E3CDD766E86D54C575D0169A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_7AA8C975995291169F3554C575D06885" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C9B8A58F463C9B9784B954C575D09D7D" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_7AA8C975995291169F3554C575D06885" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_EF62F69CC9A52B9EB35F54C575D0C966" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C9B8A58F463C9B9784B954C575D09D7D" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_EF62F69CC9A52B9EB35F54C575D0C966" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_B090200C068409452D9354C575D06827" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C9B8A58F463C9B9784B954C575D09D7D" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_B090200C068409452D9354C575D06827" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_2ACCD545400E5CFB273B54C575D0140C" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C9B8A58F463C9B9784B954C575D09D7D" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_2ACCD545400E5CFB273B54C575D0140C" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_E6D601B3A5E5C878CF8954C575D0BC58" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_C9B8A58F463C9B9784B954C575D09D7D" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_E6D601B3A5E5C878CF8954C575D0BC58" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/StockBasedCompensationTables" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D996BAB4954AC0AFB1B13AE2F8ADF9BB" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_9BC8A727765EEEB2761A3AE2F8ABA5AC" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D996BAB4954AC0AFB1B13AE2F8ADF9BB" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_9BC8A727765EEEB2761A3AE2F8ABA5AC" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_DBB2BE1AA3FB8DF1B3F13AE2F8AC1EAF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_9BC8A727765EEEB2761A3AE2F8ABA5AC" xlink:to="loc_us-gaap_AwardTypeAxis_DBB2BE1AA3FB8DF1B3F13AE2F8AC1EAF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C5B0D06C2AA0685B82D23AE2F8AC6781_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_DBB2BE1AA3FB8DF1B3F13AE2F8AC1EAF" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C5B0D06C2AA0685B82D23AE2F8AC6781_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C5B0D06C2AA0685B82D23AE2F8AC6781" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_DBB2BE1AA3FB8DF1B3F13AE2F8AC1EAF" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C5B0D06C2AA0685B82D23AE2F8AC6781" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_CAB3CAAC01E5DC4528793AE2F8ACB540" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C5B0D06C2AA0685B82D23AE2F8AC6781" xlink:to="loc_us-gaap_EmployeeStockOptionMember_CAB3CAAC01E5DC4528793AE2F8ACB540" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockAppreciationRightsSARSMember" xlink:label="loc_us-gaap_StockAppreciationRightsSARSMember_E89D935B3612217357483AE2F8AC7792" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C5B0D06C2AA0685B82D23AE2F8AC6781" xlink:to="loc_us-gaap_StockAppreciationRightsSARSMember_E89D935B3612217357483AE2F8AC7792" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="loc_us-gaap_PerformanceSharesMember_9279F50CE3D5F7956F493AE2F8AD8BE9" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C5B0D06C2AA0685B82D23AE2F8AC6781" xlink:to="loc_us-gaap_PerformanceSharesMember_9279F50CE3D5F7956F493AE2F8AD8BE9" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ScheduleOfShareBasedCompensationRestrictedStockUnitsAndCompensationExpenseTableTextBlock" xlink:label="loc_hsc_ScheduleOfShareBasedCompensationRestrictedStockUnitsAndCompensationExpenseTableTextBlock_8D9DB3F7B030E3E7DC293AE2F8AD19C9" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D996BAB4954AC0AFB1B13AE2F8ADF9BB" xlink:to="loc_hsc_ScheduleOfShareBasedCompensationRestrictedStockUnitsAndCompensationExpenseTableTextBlock_8D9DB3F7B030E3E7DC293AE2F8AD19C9" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_159817CF11C9AE10098A3AE2F8AD3FC7" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D996BAB4954AC0AFB1B13AE2F8ADF9BB" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_159817CF11C9AE10098A3AE2F8AD3FC7" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ScheduleOfShareBasedPaymentAwardInstrumentsOtherThanOptionsValuationAssumptionsTableTextBlock" xlink:label="loc_hsc_ScheduleOfShareBasedPaymentAwardInstrumentsOtherThanOptionsValuationAssumptionsTableTextBlock_E1E58D04D18B8DE53BA43AE2F8AEB03A" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D996BAB4954AC0AFB1B13AE2F8ADF9BB" xlink:to="loc_hsc_ScheduleOfShareBasedPaymentAwardInstrumentsOtherThanOptionsValuationAssumptionsTableTextBlock_E1E58D04D18B8DE53BA43AE2F8AEB03A" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationStockAppreciationRightsAwardActivityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationStockAppreciationRightsAwardActivityTableTextBlock_F4FF5C6CBCEDC86716A43AE2F8AEDCFD" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D996BAB4954AC0AFB1B13AE2F8ADF9BB" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationStockAppreciationRightsAwardActivityTableTextBlock_F4FF5C6CBCEDC86716A43AE2F8AEDCFD" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsByExercisePriceRangeTableTextBlock" xlink:label="loc_hsc_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsByExercisePriceRangeTableTextBlock_5E6F9917028ACEDAEAB13AE2F8AE9670" xlink:type="locator"/>
<link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D996BAB4954AC0AFB1B13AE2F8ADF9BB" xlink:to="loc_hsc_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockAppreciationRightsByExercisePriceRangeTableTextBlock_5E6F9917028ACEDAEAB13AE2F8AE9670" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_2A9C949AECD64449BD093AE2F8AEAB9C" xlink:type="locator"/>
<link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_D996BAB4954AC0AFB1B13AE2F8ADF9BB" xlink:to="loc_us-gaap_ScheduleOfNonvestedShareActivityTableTextBlock_2A9C949AECD64449BD093AE2F8AEAB9C" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/SubsequentEventDetails" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems_B6BF82A04F6FC0E7EA9F62F356ED5C2D" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="loc_us-gaap_SubsequentEventTable_124DCFED2AF22482D15A62F356E92CAF" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_B6BF82A04F6FC0E7EA9F62F356ED5C2D" xlink:to="loc_us-gaap_SubsequentEventTable_124DCFED2AF22482D15A62F356E92CAF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_F3965A5D83DB8C00C67462F356E925F1" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_124DCFED2AF22482D15A62F356E92CAF" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_F3965A5D83DB8C00C67462F356E925F1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09A8445A595628E3ACCA62F356E9CCA6_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_F3965A5D83DB8C00C67462F356E925F1" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09A8445A595628E3ACCA62F356E9CCA6_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09A8445A595628E3ACCA62F356E9CCA6" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_F3965A5D83DB8C00C67462F356E925F1" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09A8445A595628E3ACCA62F356E9CCA6" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ESOLMember" xlink:label="loc_hsc_ESOLMember_7A18D138F2FC441823E762F356E9F930" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09A8445A595628E3ACCA62F356E9CCA6" xlink:to="loc_hsc_ESOLMember_7A18D138F2FC441823E762F356E9F930" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_7917D1C64ABB70F17A0C62F356E92885" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_124DCFED2AF22482D15A62F356E92CAF" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_7917D1C64ABB70F17A0C62F356E92885" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_BEB8B33AC33A76F95DB462F356E98EC5_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_7917D1C64ABB70F17A0C62F356E92885" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_BEB8B33AC33A76F95DB462F356E98EC5_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_BEB8B33AC33A76F95DB462F356E98EC5" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_7917D1C64ABB70F17A0C62F356E92885" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_BEB8B33AC33A76F95DB462F356E98EC5" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_766AF3B8CB93B395884C62F3A4A075FA" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_BEB8B33AC33A76F95DB462F356E98EC5" xlink:to="loc_us-gaap_SubsequentEventMember_766AF3B8CB93B395884C62F3A4A075FA" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_5E73A4ED470EF382465A62F356ED20D3" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_B6BF82A04F6FC0E7EA9F62F356ED5C2D" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_5E73A4ED470EF382465A62F356ED20D3" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/SubsequentEventNotes" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/SubsequentEventTables" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/SummaryOfSignificantAccountingPolicies" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:type="extended">
<link:loc xlink:href="hsc-20191231.xsd#hsc_CustomerLineItems" xlink:label="loc_hsc_CustomerLineItems_00997C7BF5F3DD1DC82B591AA80C9767" xlink:type="locator"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_CustomerTable" xlink:label="loc_hsc_CustomerTable_180F4FFBBFE04EF0FB18591AA7FBA3E0" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_hsc_CustomerLineItems_00997C7BF5F3DD1DC82B591AA80C9767" xlink:to="loc_hsc_CustomerTable_180F4FFBBFE04EF0FB18591AA7FBA3E0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MajorCustomersAxis" xlink:label="loc_srt_MajorCustomersAxis_77C084D2C60166F7DD95591AA7FB66C2" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_hsc_CustomerTable_180F4FFBBFE04EF0FB18591AA7FBA3E0" xlink:to="loc_srt_MajorCustomersAxis_77C084D2C60166F7DD95591AA7FB66C2" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_88E8E0D7DC24E8D96F09591AA80BE54D_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_77C084D2C60166F7DD95591AA7FB66C2" xlink:to="loc_srt_NameOfMajorCustomerDomain_88E8E0D7DC24E8D96F09591AA80BE54D_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_88E8E0D7DC24E8D96F09591AA80BE54D" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_77C084D2C60166F7DD95591AA7FB66C2" xlink:to="loc_srt_NameOfMajorCustomerDomain_88E8E0D7DC24E8D96F09591AA80BE54D" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_SBBMember" xlink:label="loc_hsc_SBBMember_A027C5E7B96288D7405C591AA80B5FC1" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_88E8E0D7DC24E8D96F09591AA80BE54D" xlink:to="loc_hsc_SBBMember_A027C5E7B96288D7405C591AA80B5FC1" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_ChangeinMargin" xlink:label="loc_hsc_ChangeinMargin_99BD6B3AC09147E8D043591AA80CCB08" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hsc_CustomerLineItems_00997C7BF5F3DD1DC82B591AA80C9767" xlink:to="loc_hsc_ChangeinMargin_99BD6B3AC09147E8D043591AA80CCB08" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesDetails2" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesDetails3" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingenciesLineItems" xlink:label="loc_us-gaap_LossContingenciesLineItems_DC79799FF66C4CC0681441E01E06D03F" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingenciesTable" xlink:label="loc_us-gaap_LossContingenciesTable_DAF286B17382FCF90A9A41E01DF3E9AD" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_DC79799FF66C4CC0681441E01E06D03F" xlink:to="loc_us-gaap_LossContingenciesTable_DAF286B17382FCF90A9A41E01DF3E9AD" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_FEA5CAD5EBB9CC7DCFDC41E01E05A514" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_DAF286B17382FCF90A9A41E01DF3E9AD" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_FEA5CAD5EBB9CC7DCFDC41E01E05A514" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="loc_us-gaap_LossContingencyNatureDomain_2049397D9E69EC34835D41E01E050C65_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_FEA5CAD5EBB9CC7DCFDC41E01E05A514" xlink:to="loc_us-gaap_LossContingencyNatureDomain_2049397D9E69EC34835D41E01E050C65_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="loc_us-gaap_LossContingencyNatureDomain_2049397D9E69EC34835D41E01E050C65" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_FEA5CAD5EBB9CC7DCFDC41E01E05A514" xlink:to="loc_us-gaap_LossContingencyNatureDomain_2049397D9E69EC34835D41E01E050C65" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UninsuredRiskMember" xlink:label="loc_us-gaap_UninsuredRiskMember_A6756209AFE596F8A6C441E01E06A1D7" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_2049397D9E69EC34835D41E01E050C65" xlink:to="loc_us-gaap_UninsuredRiskMember_A6756209AFE596F8A6C441E01E06A1D7" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyAccrualProvision" xlink:label="loc_us-gaap_LossContingencyAccrualProvision_2CACAAA5A68C0D20024D41E01E07A3B1" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_DC79799FF66C4CC0681441E01E06D03F" xlink:to="loc_us-gaap_LossContingencyAccrualProvision_2CACAAA5A68C0D20024D41E01E07A3B1" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_LossContingencyAccrualRetrospectiveAdjustment" xlink:label="loc_hsc_LossContingencyAccrualRetrospectiveAdjustment_A50F870883B8F595814841E01E0757D1" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_DC79799FF66C4CC0681441E01E06D03F" xlink:to="loc_hsc_LossContingencyAccrualRetrospectiveAdjustment_A50F870883B8F595814841E01E0757D1" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyAccrualAtCarryingValue" xlink:label="loc_us-gaap_LossContingencyAccrualAtCarryingValue_128133B2CBEC1FD76B1E41E01E070849" xlink:type="locator"/>
<link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_DC79799FF66C4CC0681441E01E06D03F" xlink:to="loc_us-gaap_LossContingencyAccrualAtCarryingValue_128133B2CBEC1FD76B1E41E01E070849" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyReceivable" xlink:label="loc_us-gaap_LossContingencyReceivable_3C536854F8ED49B33D1F41E01E073422" xlink:type="locator"/>
<link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_DC79799FF66C4CC0681441E01E06D03F" xlink:to="loc_us-gaap_LossContingencyReceivable_3C536854F8ED49B33D1F41E01E073422" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesDetails4" xlink:type="extended">
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_884A63D429AEC4038D0D5F8AEB946A10" xlink:type="locator"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_45F3EE0DA2A33111FE2E5F8AEB92C79E" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_884A63D429AEC4038D0D5F8AEB946A10" xlink:to="loc_us-gaap_DerivativeTable_45F3EE0DA2A33111FE2E5F8AEB92C79E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_0BC5356C4D6A635CB26C5F8AEB928341" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_45F3EE0DA2A33111FE2E5F8AEB92C79E" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_0BC5356C4D6A635CB26C5F8AEB928341" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_CF95E5D4A2000D616F025F8AEB924634_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_0BC5356C4D6A635CB26C5F8AEB928341" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_CF95E5D4A2000D616F025F8AEB924634_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_CF95E5D4A2000D616F025F8AEB924634" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_0BC5356C4D6A635CB26C5F8AEB928341" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_CF95E5D4A2000D616F025F8AEB924634" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignExchangeForwardMember" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_0E19C1BC567733A5AFCC5F8AEB925C4F" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_CF95E5D4A2000D616F025F8AEB924634" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_0E19C1BC567733A5AFCC5F8AEB925C4F" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_92284B4F0374285C0DD05F8AEB92B6BF" xlink:type="locator"/>
<link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_45F3EE0DA2A33111FE2E5F8AEB92C79E" xlink:to="loc_srt_RangeAxis_92284B4F0374285C0DD05F8AEB92B6BF" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_F9DD67E100390062A4D25F8AEB926421_default" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_92284B4F0374285C0DD05F8AEB92B6BF" xlink:to="loc_srt_RangeMember_F9DD67E100390062A4D25F8AEB926421_default" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_F9DD67E100390062A4D25F8AEB926421" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_92284B4F0374285C0DD05F8AEB92B6BF" xlink:to="loc_srt_RangeMember_F9DD67E100390062A4D25F8AEB926421" xlink:type="arc"/>
<link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_63AEFE9E45629DEC8D605F8AEB92B479" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_F9DD67E100390062A4D25F8AEB926421" xlink:to="loc_srt_MaximumMember_63AEFE9E45629DEC8D605F8AEB92B479" xlink:type="arc"/>
<link:loc xlink:href="hsc-20191231.xsd#hsc_DerivativeMaturityPeriod" xlink:label="loc_hsc_DerivativeMaturityPeriod_841F9CE8E5A69482209B5F8AEB940401" xlink:type="locator"/>
<link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_884A63D429AEC4038D0D5F8AEB946A10" xlink:to="loc_hsc_DerivativeMaturityPeriod_841F9CE8E5A69482209B5F8AEB940401" xlink:type="arc"/>
</link:definitionLink>
<link:definitionLink xlink:role="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended"/>
<link:definitionLink xlink:role="http://www.harsco.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:type="extended"/>
</link:linkbase>


2 Subsequent Filings that Reference this Filing

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 2/24/22  Enviri Corp.                      10-K       12/31/21  131:24M
 2/25/21  Enviri Corp.                      10-K       12/31/20  124:25M
Top
Filing Submission 0000045876-20-000026   –   Alternative Formats (Word / Rich Text, HTML, Plain Text, et al.)

Copyright © 2024 Fran Finnegan & Company LLC – All Rights Reserved.
AboutPrivacyRedactionsHelp — Sun., Apr. 28, 9:59:15.2pm ET