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

Global Industrial Co. – ‘10-K’ for 12/31/20 – ‘EX-101.DEF’

On:  Thursday, 3/18/21, at 4:44pm ET   ·   For:  12/31/20   ·   Accession #:  945114-21-10   ·   File #:  1-13792

Previous ‘10-K’:  ‘10-K’ on 3/13/20 for 12/31/19   ·   Next:  ‘10-K’ on 3/17/22 for 12/31/21   ·   Latest:  ‘10-K’ on 3/12/24 for 12/31/23   ·   17 References:   

Find Words in Filings emoji
 
  in    Show  and   Hints

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

 3/18/21  Systemax Inc.                     10-K       12/31/20   87:9.3M

Annual Report   —   Form 10-K
Filing Table of Contents

Document/Exhibit                   Description                      Pages   Size 

 1: 10-K        Annual Report                                       HTML   1.10M 
 2: EX-10.21    Material Contract                                   HTML     97K 
 3: EX-21       Subsidiaries List                                   HTML     26K 
 4: EX-23       Consent of Expert or Counsel                        HTML     23K 
 5: EX-31.1     Certification -- §302 - SOA'02                      HTML     27K 
 6: EX-31.2     Certification -- §302 - SOA'02                      HTML     27K 
 7: EX-32.1     Certification -- §906 - SOA'02                      HTML     23K 
 8: EX-32.2     Certification -- §906 - SOA'02                      HTML     23K 
15: R1          Cover                                               HTML     84K 
16: R2          Consolidated Balance Sheets                         HTML    105K 
17: R3          Consolidated Balance Sheets (Parenthetical)         HTML     44K 
18: R4          Consolidated Statements of Operations               HTML    121K 
19: R5          Consolidated Statements of Comprehensive Income     HTML     39K 
                (Loss)                                                           
20: R6          Consolidated Statements of Cash Flows               HTML    117K 
21: R7          Consolidated Statements of Cash Flows               HTML     31K 
                (Parenthetical)                                                  
22: R8          Consolidated Statements of Shareholders' Equity     HTML     91K 
23: R9          Basis of Presentation                               HTML     31K 
24: R10         Summary of Significant Accounting Policies          HTML     66K 
25: R11         Credit Losses                                       HTML     32K 
26: R12         Leases                                              HTML     42K 
27: R13         Revenue                                             HTML     37K 
28: R14         Dispositions and Special Gains and Charges          HTML     64K 
29: R15         Goodwill and Intangibles                            HTML     60K 
30: R16         Property, Plant and Equipment                       HTML     34K 
31: R17         Credit Facilities                                   HTML     26K 
32: R18         Accrued Expenses and Other Current Liabilities      HTML     35K 
33: R19         Stock Repurchases                                   HTML    149K 
34: R20         Shareholders' Equity                                HTML    149K 
35: R21         Income Taxes                                        HTML    104K 
36: R22         Commitments, Contingencies and Other Matters        HTML     28K 
37: R23         Subsequent Event                                    HTML     25K 
38: R24         Quarterly Financial Data (Unaudited)                HTML     53K 
39: R25         Schedule Ii - Valuation and Qualifying Accounts     HTML     57K 
40: R26         Summary of Significant Accounting Policies          HTML    121K 
                (Policies)                                                       
41: R27         Credit Losses (Tables)                              HTML     29K 
42: R28         Leases (Tables)                                     HTML     42K 
43: R29         Revenue (Tables)                                    HTML     33K 
44: R30         Dispositions and Special Gains and Charges          HTML     66K 
                (Tables)                                                         
45: R31         Goodwill and Intangibles (Tables)                   HTML     66K 
46: R32         Property, Plant and Equipment (Tables)              HTML     34K 
47: R33         Accrued Expenses and Other Current Liabilities      HTML     36K 
                (Tables)                                                         
48: R34         Shareholders' Equity (Tables)                       HTML    150K 
49: R35         Income Taxes (Tables)                               HTML    105K 
50: R36         Quarterly Financial Data (Unaudited) (Tables)       HTML     53K 
51: R37         Basis of Presentation (Details)                     HTML     57K 
52: R38         Summary of Significant Accounting Policies          HTML     86K 
                (Details)                                                        
53: R39         Credit Losses (Details)                             HTML     34K 
54: R40         Leases (Details)                                    HTML     32K 
55: R41         Leases - Lease Expense (Details)                    HTML     30K 
56: R42         LEASES - Maturities of Lease Liabilities (Details)  HTML     41K 
57: R43         Revenue (Details)                                   HTML     36K 
58: R44         DISPOSITIONS AND SPECIAL GAINS AND CHARGES -        HTML     61K 
                Narrative (Details)                                              
59: R45         DISPOSITIONS AND SPECIAL GAINS AND CHARGES -        HTML     68K 
                Discontinued Operations (Details)                                
60: R46         DISPOSITIONS AND SPECIAL GAINS AND CHARGES -        HTML     30K 
                Special Charges (Details)                                        
61: R47         GOODWILL AND INTANGIBLES - Goodwill and             HTML     27K 
                Indefinite-Lived Intangible Assets (Details)                     
62: R48         GOODWILL AND INTANGIBLES - Definite-Lived           HTML     44K 
                Intangible Assets (Details)                                      
63: R49         GOODWILL AND INTANGIBLES - Schedule of              HTML     37K 
                Amortization Expense (Details)                                   
64: R50         PROPERTY, PLANT AND EQUIPMENT - Schedule of         HTML     44K 
                Property, Plant, and Equipment (Details)                         
65: R51         Credit Facilities (Details)                         HTML     44K 
66: R52         Accrued Expenses and Other Current Liabilities      HTML     43K 
                (Details)                                                        
67: R53         Stock Repurchases (Details)                         HTML     31K 
68: R54         SHAREHOLDERS' EQUITY - Narrative (Details)          HTML    117K 
69: R55         SHAREHOLDERS' EQUITY - Weighted-Average             HTML     34K 
                Assumptions Used to Estimate Fair Value of Options               
                (Details)                                                        
70: R56         SHAREHOLDERS' EQUITY - Options Outstanding and      HTML     51K 
                Exercisable (Details)                                            
71: R57         SHAREHOLDERS' EQUITY - Options Vested and           HTML     57K 
                Exercisable or Nonvested that are Expected to Vest               
                (Details)                                                        
72: R58         SHAREHOLDERS' EQUITY - Unvested Stock Options       HTML     47K 
                (Details)                                                        
73: R59         SHAREHOLDERS' EQUITY - Restricted Stock Awards      HTML     84K 
                (Details)                                                        
74: R60         SHAREHOLDERS' EQUITY - Unvested Restricted Stock    HTML     47K 
                (Details)                                                        
75: R61         INCOME TAXES - Income (Loss) from Continuing        HTML     33K 
                Operations Before Income Taxes (Details)                         
76: R62         Income Taxes - (Benefit) Provision for Income       HTML     51K 
                Taxes (Details)                                                  
77: R63         Income Taxes - Narrative (Details)                  HTML     52K 
78: R64         INCOME TAXES - Reconciliation Between Income Tax    HTML     66K 
                Expense and Computed Income Tax Expense (Details)                
79: R65         INCOME TAXES - Deferred Tax Assets and Liabilities  HTML     44K 
                (Details)                                                        
80: R66         COMMITMENTS, CONTINGENCIES AND OTHER MATTERS -      HTML     26K 
                Narrative (Details)                                              
81: R67         Subsequent Event (Details)                          HTML     28K 
82: R68         Quarterly Financial Data (Unaudited) (Details)      HTML     53K 
83: R69         Schedule Ii - Valuation and Qualifying Accounts     HTML     37K 
                (Details)                                                        
85: XML         IDEA XML File -- Filing Summary                      XML    151K 
14: XML         XBRL Instance -- syx-20201231_htm                    XML   2.24M 
84: EXCEL       IDEA Workbook of Financial Reports                  XLSX    106K 
10: EX-101.CAL  XBRL Calculations -- syx-20201231_cal                XML    261K 
11: EX-101.DEF  XBRL Definitions -- syx-20201231_def                 XML    601K 
12: EX-101.LAB  XBRL Labels -- syx-20201231_lab                      XML   1.74M 
13: EX-101.PRE  XBRL Presentations -- syx-20201231_pre               XML   1.03M 
 9: EX-101.SCH  XBRL Schema -- syx-20201231                          XSD    155K 
86: JSON        XBRL Instance as JSON Data -- MetaLinks              405±   597K 
87: ZIP         XBRL Zipped Folder -- 0000945114-21-000010-xbrl      Zip    364K 


‘EX-101.DEF’   —   XBRL Definitions — syx-20201231_def


This Exhibit is an XBRL XML File.


                                                                                                                                                                                
<?xml version="1.0" encoding="windows-1252"?>
<!-- XBRL Document Created with Wdesk from Workiva -->
<!-- Copyright 2021 Workiva -->
<!-- r:3894c759-fc5e-442a-baff-b9d27693beec,g:d31f3330-132d-4d59-9b71-13dddf43f78c -->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
<link:roleRef roleURI="http://systemax.com/role/Cover" xlink:type="simple" xlink:href="syx-20201231.xsd#Cover"/>
<link:definitionLink xlink:role="http://systemax.com/role/Cover" xlink:type="extended" id="i1d09cace09e04eb7b8138d2e0deba111_Cover"/>
<link:roleRef roleURI="http://systemax.com/role/CONSOLIDATEDBALANCESHEETS" xlink:type="simple" xlink:href="syx-20201231.xsd#CONSOLIDATEDBALANCESHEETS"/>
<link:definitionLink xlink:role="http://systemax.com/role/CONSOLIDATEDBALANCESHEETS" xlink:type="extended" id="if6b79e0056a740b9ac0e991f8a73d0a2_CONSOLIDATEDBALANCESHEETS"/>
<link:roleRef roleURI="http://systemax.com/role/CONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="simple" xlink:href="syx-20201231.xsd#CONSOLIDATEDBALANCESHEETSParenthetical"/>
<link:definitionLink xlink:role="http://systemax.com/role/CONSOLIDATEDBALANCESHEETSParenthetical" xlink:type="extended" id="i95de59a729b04db794797d288c78a1fd_CONSOLIDATEDBALANCESHEETSParenthetical"/>
<link:roleRef roleURI="http://systemax.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="simple" xlink:href="syx-20201231.xsd#CONSOLIDATEDSTATEMENTSOFOPERATIONS"/>
<link:definitionLink xlink:role="http://systemax.com/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="extended" id="i21dfd66a6bb44bfc9608c59b27d018e1_CONSOLIDATEDSTATEMENTSOFOPERATIONS"/>
<link:roleRef roleURI="http://systemax.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS" xlink:type="simple" xlink:href="syx-20201231.xsd#CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS"/>
<link:definitionLink xlink:role="http://systemax.com/role/CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS" xlink:type="extended" id="i1ce3d76968c94427b80e85a822552c46_CONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS"/>
<link:roleRef roleURI="http://systemax.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="simple" xlink:href="syx-20201231.xsd#CONSOLIDATEDSTATEMENTSOFCASHFLOWS"/>
<link:definitionLink xlink:role="http://systemax.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="extended" id="i1fa416de943540ee9c33b737a17658f2_CONSOLIDATEDSTATEMENTSOFCASHFLOWS"/>
<link:roleRef roleURI="http://systemax.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWSParenthetical" xlink:type="simple" xlink:href="syx-20201231.xsd#CONSOLIDATEDSTATEMENTSOFCASHFLOWSParenthetical"/>
<link:definitionLink xlink:role="http://systemax.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWSParenthetical" xlink:type="extended" id="ic819a4e45cea472c894410f67e37fe6e_CONSOLIDATEDSTATEMENTSOFCASHFLOWSParenthetical"/>
<link:roleRef roleURI="http://systemax.com/role/CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:type="simple" xlink:href="syx-20201231.xsd#CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY"/>
<link:definitionLink xlink:role="http://systemax.com/role/CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:type="extended" id="id6f240d215b0448abef79e19f5a2d64a_CONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_b1147326-8280-4add-b64b-21ed0cc50872" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b1147326-8280-4add-b64b-21ed0cc50872" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_2ad388de-1625-44a4-b37e-5b9ad34f47bf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesOutstanding"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_SharesOutstanding_2ad388de-1625-44a4-b37e-5b9ad34f47bf" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_71069780-a05c-4514-9486-b78dcbd4c76b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_StockholdersEquity_71069780-a05c-4514-9486-b78dcbd4c76b" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_e321ae92-1901-4bb4-ad2c-e743e9e3b42a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_e321ae92-1901-4bb4-ad2c-e743e9e3b42a" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_81a48f52-dfa4-4779-b6ac-784657b608ce" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_81a48f52-dfa4-4779-b6ac-784657b608ce" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross_da5699e7-76f6-4408-9120-030fd188ef8a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross_da5699e7-76f6-4408-9120-030fd188ef8a" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_81adfa11-45f2-42ab-a7ee-3f5e7a3c3264" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_81adfa11-45f2-42ab-a7ee-3f5e7a3c3264" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_4acaa17c-06d9-4f8f-ac6d-112e44158b90" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_4acaa17c-06d9-4f8f-ac6d-112e44158b90" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross_2e1522b2-be4b-46cf-b877-1162fab83a46" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross_2e1522b2-be4b-46cf-b877-1162fab83a46" xlink:type="arc" order="8"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensationGross_e36d40c3-1ff9-47f7-8126-48445db2903d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockGrantedDuringPeriodValueSharebasedCompensationGross"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensationGross_e36d40c3-1ff9-47f7-8126-48445db2903d" xlink:type="arc" order="9"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock_2abdfffd-8457-4721-9bb8-b3412356ec2a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsCommonStock"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_DividendsCommonStock_2abdfffd-8457-4721-9bb8-b3412356ec2a" xlink:type="arc" order="10"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_d4597d11-c28f-4087-87b3-804f42a00bb1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockSharesAcquired"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_d4597d11-c28f-4087-87b3-804f42a00bb1" xlink:type="arc" order="11"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_587ebdca-6a5b-46e9-869a-e4ed6af35264" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_587ebdca-6a5b-46e9-869a-e4ed6af35264" xlink:type="arc" order="12"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_DiscontinuedFranceEntitiesCumulativeTranslationAdjustment_2e811efc-b69f-40b2-9108-3886e0b26d80" xlink:href="syx-20201231.xsd#syx_DiscontinuedFranceEntitiesCumulativeTranslationAdjustment"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_syx_DiscontinuedFranceEntitiesCumulativeTranslationAdjustment_2e811efc-b69f-40b2-9108-3886e0b26d80" xlink:type="arc" order="13"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_5969a425-5d22-448f-9266-e651488c80f0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_5969a425-5d22-448f-9266-e651488c80f0" xlink:type="arc" order="14"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_c4e7767f-ecb5-42c4-bf87-58df16a09826" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_c4e7767f-ecb5-42c4-bf87-58df16a09826" xlink:type="arc" order="15"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_6f2b6c7a-49da-4a4f-a37c-a6c83846a352" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_6f2b6c7a-49da-4a4f-a37c-a6c83846a352" xlink:type="arc" order="16"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_532b597b-ffdc-40fc-a01c-3f0454f95c95" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_45bd8f7b-231e-4273-89b5-ad30e98af204" xlink:to="loc_us-gaap_NetIncomeLoss_532b597b-ffdc-40fc-a01c-3f0454f95c95" xlink:type="arc" order="17"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_cf54942b-f5d6-4220-83b8-0f6121354069" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesOutstanding"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_6c2a434c-eb4c-4368-b370-885650b67855" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_5e741503-747f-408a-bbb8-f725989a6d54" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_b1147326-8280-4add-b64b-21ed0cc50872" xlink:to="loc_us-gaap_StatementTable_5e741503-747f-408a-bbb8-f725989a6d54" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_59bb2c90-0736-4ad3-ada1-7412e44bc34e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_5e741503-747f-408a-bbb8-f725989a6d54" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_59bb2c90-0736-4ad3-ada1-7412e44bc34e" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_59bb2c90-0736-4ad3-ada1-7412e44bc34e_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_59bb2c90-0736-4ad3-ada1-7412e44bc34e" xlink:to="loc_us-gaap_EquityComponentDomain_59bb2c90-0736-4ad3-ada1-7412e44bc34e_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_8d923714-a40a-422b-923a-c605f0dca529" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_59bb2c90-0736-4ad3-ada1-7412e44bc34e" xlink:to="loc_us-gaap_EquityComponentDomain_8d923714-a40a-422b-923a-c605f0dca529" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_6348cfe9-ec2e-4a8b-802e-0bf63a9dc802" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8d923714-a40a-422b-923a-c605f0dca529" xlink:to="loc_us-gaap_CommonStockMember_6348cfe9-ec2e-4a8b-802e-0bf63a9dc802" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_76ccef4a-4c2d-4a4c-a3fa-f5c6f98d475d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8d923714-a40a-422b-923a-c605f0dca529" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_76ccef4a-4c2d-4a4c-a3fa-f5c6f98d475d" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockMember_f2b1c283-dd4e-4fc0-a56e-5ac225a5a39f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8d923714-a40a-422b-923a-c605f0dca529" xlink:to="loc_us-gaap_TreasuryStockMember_f2b1c283-dd4e-4fc0-a56e-5ac225a5a39f" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_0ca774a3-6c91-4e6f-bb1a-13e029f1c888" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8d923714-a40a-422b-923a-c605f0dca529" xlink:to="loc_us-gaap_RetainedEarningsMember_0ca774a3-6c91-4e6f-bb1a-13e029f1c888" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_99b235f0-7b62-41c4-b4ad-e55fd5c51e21" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8d923714-a40a-422b-923a-c605f0dca529" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_99b235f0-7b62-41c4-b4ad-e55fd5c51e21" xlink:type="arc" order="4"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/BASISOFPRESENTATION" xlink:type="simple" xlink:href="syx-20201231.xsd#BASISOFPRESENTATION"/>
<link:definitionLink xlink:role="http://systemax.com/role/BASISOFPRESENTATION" xlink:type="extended" id="if51c233effba4f749c7d52d003caeb56_BASISOFPRESENTATION"/>
<link:roleRef roleURI="http://systemax.com/role/BASISOFPRESENTATIONDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#BASISOFPRESENTATIONDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/BASISOFPRESENTATIONDetails" xlink:type="extended" id="i7232fbcc647847f086cd85f1805b98d5_BASISOFPRESENTATIONDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_78105694-1265-42ca-9672-55c7b58a8eb3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_b3e69368-c4c4-42c7-a2c0-9ca87d05b171" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NumberOfReportableSegments"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_78105694-1265-42ca-9672-55c7b58a8eb3" xlink:to="loc_us-gaap_NumberOfReportableSegments_b3e69368-c4c4-42c7-a2c0-9ca87d05b171" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_8899d14f-be72-4a01-8982-86646801d306" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_78105694-1265-42ca-9672-55c7b58a8eb3" xlink:to="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_8899d14f-be72-4a01-8982-86646801d306" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_965253b9-65f2-493a-9199-051028b99d02" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_78105694-1265-42ca-9672-55c7b58a8eb3" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_965253b9-65f2-493a-9199-051028b99d02" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_DisposalGroupNotDiscontinuedOperationNetGainLossOnDisposal_ce681834-cf50-42a8-bcdf-f345428b00a0" xlink:href="syx-20201231.xsd#syx_DisposalGroupNotDiscontinuedOperationNetGainLossOnDisposal"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_78105694-1265-42ca-9672-55c7b58a8eb3" xlink:to="loc_syx_DisposalGroupNotDiscontinuedOperationNetGainLossOnDisposal_ce681834-cf50-42a8-bcdf-f345428b00a0" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_8eb9ecdd-3ae8-4111-87b9-0aee159a3f79" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_78105694-1265-42ca-9672-55c7b58a8eb3" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_8eb9ecdd-3ae8-4111-87b9-0aee159a3f79" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_GainFromSettlementOfStateAudit_08319311-9e70-4084-a650-24e78e70cc65" xlink:href="syx-20201231.xsd#syx_GainFromSettlementOfStateAudit"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_78105694-1265-42ca-9672-55c7b58a8eb3" xlink:to="loc_syx_GainFromSettlementOfStateAudit_08319311-9e70-4084-a650-24e78e70cc65" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionPurchasesFromRelatedParty_0caa2812-8c6e-4b80-836f-4623d7e7ac38" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionPurchasesFromRelatedParty"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_78105694-1265-42ca-9672-55c7b58a8eb3" xlink:to="loc_us-gaap_RelatedPartyTransactionPurchasesFromRelatedParty_0caa2812-8c6e-4b80-836f-4623d7e7ac38" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_367b42c7-beab-4f8c-9b12-8c7e72df056d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_78105694-1265-42ca-9672-55c7b58a8eb3" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_367b42c7-beab-4f8c-9b12-8c7e72df056d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_507f0421-7e0f-49f9-a41e-a276796e22fd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_367b42c7-beab-4f8c-9b12-8c7e72df056d" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_507f0421-7e0f-49f9-a41e-a276796e22fd" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_507f0421-7e0f-49f9-a41e-a276796e22fd_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_507f0421-7e0f-49f9-a41e-a276796e22fd" xlink:to="loc_us-gaap_SegmentDomain_507f0421-7e0f-49f9-a41e-a276796e22fd_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_0d32d3df-30eb-4806-8471-4ffabfc2935c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_507f0421-7e0f-49f9-a41e-a276796e22fd" xlink:to="loc_us-gaap_SegmentDomain_0d32d3df-30eb-4806-8471-4ffabfc2935c" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_ETGDiscontinuedMember_40c2c05a-7f26-4d52-bf17-fc16c595ac00" xlink:href="syx-20201231.xsd#syx_ETGDiscontinuedMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0d32d3df-30eb-4806-8471-4ffabfc2935c" xlink:to="loc_syx_ETGDiscontinuedMember_40c2c05a-7f26-4d52-bf17-fc16c595ac00" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_fce45bc5-9fd3-467c-8474-4c425c065188" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupClassificationAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_367b42c7-beab-4f8c-9b12-8c7e72df056d" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_fce45bc5-9fd3-467c-8474-4c425c065188" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_fce45bc5-9fd3-467c-8474-4c425c065188_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupClassificationDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_fce45bc5-9fd3-467c-8474-4c425c065188" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_fce45bc5-9fd3-467c-8474-4c425c065188_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_92f5acd3-817f-4d86-a249-46d56e6aed74" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupClassificationDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_fce45bc5-9fd3-467c-8474-4c425c065188" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_92f5acd3-817f-4d86-a249-46d56e6aed74" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_09245aef-9758-4640-8336-b0af062434b5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DiscontinuedOperationsDisposedOfBySaleMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_92f5acd3-817f-4d86-a249-46d56e6aed74" xlink:to="loc_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_09245aef-9758-4640-8336-b0af062434b5" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_e8d130d4-806c-460d-b18a-993cc81374fc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_367b42c7-beab-4f8c-9b12-8c7e72df056d" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_e8d130d4-806c-460d-b18a-993cc81374fc" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_e8d130d4-806c-460d-b18a-993cc81374fc_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_e8d130d4-806c-460d-b18a-993cc81374fc" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_e8d130d4-806c-460d-b18a-993cc81374fc_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1db24f73-9647-40c7-b1c3-f6f60535ac52" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_e8d130d4-806c-460d-b18a-993cc81374fc" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1db24f73-9647-40c7-b1c3-f6f60535ac52" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_FrenchBusinessUnitMember_e660f858-7e5e-4943-8f23-9e74856476be" xlink:href="syx-20201231.xsd#syx_FrenchBusinessUnitMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1db24f73-9647-40c7-b1c3-f6f60535ac52" xlink:to="loc_syx_FrenchBusinessUnitMember_e660f858-7e5e-4943-8f23-9e74856476be" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_SARLBusinessSegmentMember_cbc96f07-b373-4a4d-94b0-a79dd7d5919d" xlink:href="syx-20201231.xsd#syx_SARLBusinessSegmentMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1db24f73-9647-40c7-b1c3-f6f60535ac52" xlink:to="loc_syx_SARLBusinessSegmentMember_cbc96f07-b373-4a4d-94b0-a79dd7d5919d" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_NorthAmericanTechnologyProductsSegmentMember_edd6a061-f8af-4b94-b607-851de7dff35e" xlink:href="syx-20201231.xsd#syx_NorthAmericanTechnologyProductsSegmentMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1db24f73-9647-40c7-b1c3-f6f60535ac52" xlink:to="loc_syx_NorthAmericanTechnologyProductsSegmentMember_edd6a061-f8af-4b94-b607-851de7dff35e" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_491532c7-be93-485b-9778-78afd60b8d29" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_367b42c7-beab-4f8c-9b12-8c7e72df056d" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_491532c7-be93-485b-9778-78afd60b8d29" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_491532c7-be93-485b-9778-78afd60b8d29_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_491532c7-be93-485b-9778-78afd60b8d29" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_491532c7-be93-485b-9778-78afd60b8d29_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_eeeff278-01d4-4ba8-a698-101deea6ba9a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_491532c7-be93-485b-9778-78afd60b8d29" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_eeeff278-01d4-4ba8-a698-101deea6ba9a" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_InventoryPurchasesMember_8ddb8984-8272-47b0-97cb-1477d7ea8b1e" xlink:href="syx-20201231.xsd#syx_InventoryPurchasesMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_eeeff278-01d4-4ba8-a698-101deea6ba9a" xlink:to="loc_syx_InventoryPurchasesMember_8ddb8984-8272-47b0-97cb-1477d7ea8b1e" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_6d13ab11-fbc9-4d1d-aa02-47653e9d0004" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_367b42c7-beab-4f8c-9b12-8c7e72df056d" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_6d13ab11-fbc9-4d1d-aa02-47653e9d0004" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_6d13ab11-fbc9-4d1d-aa02-47653e9d0004_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_6d13ab11-fbc9-4d1d-aa02-47653e9d0004" xlink:to="loc_us-gaap_RelatedPartyDomain_6d13ab11-fbc9-4d1d-aa02-47653e9d0004_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_a91e74cb-5c56-445c-b4f7-3a28f55786bb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RelatedPartyDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_6d13ab11-fbc9-4d1d-aa02-47653e9d0004" xlink:to="loc_us-gaap_RelatedPartyDomain_a91e74cb-5c56-445c-b4f7-3a28f55786bb" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImmediateFamilyMemberOfManagementOrPrincipalOwnerMember_9ad59924-84b1-451b-9325-bca1ca2714e6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImmediateFamilyMemberOfManagementOrPrincipalOwnerMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_a91e74cb-5c56-445c-b4f7-3a28f55786bb" xlink:to="loc_us-gaap_ImmediateFamilyMemberOfManagementOrPrincipalOwnerMember_9ad59924-84b1-451b-9325-bca1ca2714e6" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES" xlink:type="simple" xlink:href="syx-20201231.xsd#SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES"/>
<link:definitionLink xlink:role="http://systemax.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES" xlink:type="extended" id="ie205e857b1714342a96b2747766f8cc2_SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES"/>
<link:roleRef roleURI="http://systemax.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies" xlink:type="simple" xlink:href="syx-20201231.xsd#SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies"/>
<link:definitionLink xlink:role="http://systemax.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies" xlink:type="extended" id="id5bfebb4b50c4ec1b5818f2954fb0182_SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies"/>
<link:roleRef roleURI="http://systemax.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESDetails" xlink:type="extended" id="i7d721b6da2b54a2facbbbf844049ac72_SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_edc063b4-3dd8-43d1-8c34-6faef8d0fbd8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentReportingInformationLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAbstract_1ee41346-90e3-4756-9653-4fbb27103e9c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedCashAbstract"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_edc063b4-3dd8-43d1-8c34-6faef8d0fbd8" xlink:to="loc_us-gaap_RestrictedCashAbstract_1ee41346-90e3-4756-9653-4fbb27103e9c" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_5e1ece42-7635-4f1a-bdaf-a65946df3aa6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAbstract_1ee41346-90e3-4756-9653-4fbb27103e9c" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_5e1ece42-7635-4f1a-bdaf-a65946df3aa6" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_6a06f50e-9a9f-4060-b20e-64e7ccbfd47a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_edc063b4-3dd8-43d1-8c34-6faef8d0fbd8" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAbstract_6a06f50e-9a9f-4060-b20e-64e7ccbfd47a" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_c8992243-31e5-4c1e-9096-64aa356a2dc2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_6a06f50e-9a9f-4060-b20e-64e7ccbfd47a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_c8992243-31e5-4c1e-9096-64aa356a2dc2" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentDisposals_c37a7fd6-5f75-456f-b1f4-ff47df4fcfcc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentDisposals"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_6a06f50e-9a9f-4060-b20e-64e7ccbfd47a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentDisposals_c37a7fd6-5f75-456f-b1f4-ff47df4fcfcc" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentOtherAccumulatedDepreciation_18a3edc0-f510-41d1-84e2-b94675c79cb4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentOtherAccumulatedDepreciation"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_6a06f50e-9a9f-4060-b20e-64e7ccbfd47a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentOtherAccumulatedDepreciation_18a3edc0-f510-41d1-84e2-b94675c79cb4" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_9323346b-9f5c-470c-8b0b-7ff3d66b4a0e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenuesAbstract"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_edc063b4-3dd8-43d1-8c34-6faef8d0fbd8" xlink:to="loc_us-gaap_RevenuesAbstract_9323346b-9f5c-470c-8b0b-7ff3d66b4a0e" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerRefundLiability_45b83bb5-f41c-40bb-b4aa-8dcef5d6fe1e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerRefundLiability"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_9323346b-9f5c-470c-8b0b-7ff3d66b4a0e" xlink:to="loc_us-gaap_ContractWithCustomerRefundLiability_45b83bb5-f41c-40bb-b4aa-8dcef5d6fe1e" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketingAndAdvertisingExpenseAbstract_a76bd904-0cb9-4746-8ed1-24abc6de6b43" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MarketingAndAdvertisingExpenseAbstract"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_edc063b4-3dd8-43d1-8c34-6faef8d0fbd8" xlink:to="loc_us-gaap_MarketingAndAdvertisingExpenseAbstract_a76bd904-0cb9-4746-8ed1-24abc6de6b43" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdvertisingExpense_5ef30840-94ab-4775-a698-0dfbdcbb5ae6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdvertisingExpense"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MarketingAndAdvertisingExpenseAbstract_a76bd904-0cb9-4746-8ed1-24abc6de6b43" xlink:to="loc_us-gaap_AdvertisingExpense_5ef30840-94ab-4775-a698-0dfbdcbb5ae6" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_f60e84ee-0687-4c39-b227-61403c5076c1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareAbstract"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_edc063b4-3dd8-43d1-8c34-6faef8d0fbd8" xlink:to="loc_us-gaap_EarningsPerShareAbstract_f60e84ee-0687-4c39-b227-61403c5076c1" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic_c5de071d-91a2-4efd-8125-2e05bb5e54b8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_f60e84ee-0687-4c39-b227-61403c5076c1" xlink:to="loc_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersBasic_c5de071d-91a2-4efd-8125-2e05bb5e54b8" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted_ec8ab388-72cc-4491-8651-3086217efa5c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_f60e84ee-0687-4c39-b227-61403c5076c1" xlink:to="loc_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted_ec8ab388-72cc-4491-8651-3086217efa5c" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersBasic_d9b8337e-6546-419a-a543-dd68a8d4dfee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersBasic"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_f60e84ee-0687-4c39-b227-61403c5076c1" xlink:to="loc_us-gaap_NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersBasic_d9b8337e-6546-419a-a543-dd68a8d4dfee" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersDiluted_75d993c3-4dce-43ab-a7b2-39571164826f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersDiluted"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_f60e84ee-0687-4c39-b227-61403c5076c1" xlink:to="loc_us-gaap_NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersDiluted_75d993c3-4dce-43ab-a7b2-39571164826f" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_15d687b9-4b09-4e28-833f-5439811fe369" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_f60e84ee-0687-4c39-b227-61403c5076c1" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_15d687b9-4b09-4e28-833f-5439811fe369" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_8f747aac-634d-4c74-a5c3-5a63188cd682" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_f60e84ee-0687-4c39-b227-61403c5076c1" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_8f747aac-634d-4c74-a5c3-5a63188cd682" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_fec9c090-72ee-4a97-a2a0-f471779a28ca" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_f60e84ee-0687-4c39-b227-61403c5076c1" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_fec9c090-72ee-4a97-a2a0-f471779a28ca" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementBenefitExpenseAbstract_c577a47c-4e26-4de0-b5f1-b4777a94f5ec" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PensionAndOtherPostretirementBenefitExpenseAbstract"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_edc063b4-3dd8-43d1-8c34-6faef8d0fbd8" xlink:to="loc_us-gaap_PensionAndOtherPostretirementBenefitExpenseAbstract_c577a47c-4e26-4de0-b5f1-b4777a94f5ec" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_DefinedContributionPlanMinimumAnnualContributionPerEmployeePercent_073c5bc2-370e-491f-8ba1-aeabc36e4727" xlink:href="syx-20201231.xsd#syx_DefinedContributionPlanMinimumAnnualContributionPerEmployeePercent"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PensionAndOtherPostretirementBenefitExpenseAbstract_c577a47c-4e26-4de0-b5f1-b4777a94f5ec" xlink:to="loc_syx_DefinedContributionPlanMinimumAnnualContributionPerEmployeePercent_073c5bc2-370e-491f-8ba1-aeabc36e4727" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized_ccfdf3b3-69a3-43d0-b917-c2a29cc3ff57" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedContributionPlanCostRecognized"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PensionAndOtherPostretirementBenefitExpenseAbstract_c577a47c-4e26-4de0-b5f1-b4777a94f5ec" xlink:to="loc_us-gaap_DefinedContributionPlanCostRecognized_ccfdf3b3-69a3-43d0-b917-c2a29cc3ff57" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract_592c5a7a-a05c-48e0-a5b3-6377c42cb6ad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueDisclosuresAbstract"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_edc063b4-3dd8-43d1-8c34-6faef8d0fbd8" xlink:to="loc_us-gaap_FairValueDisclosuresAbstract_592c5a7a-a05c-48e0-a5b3-6377c42cb6ad" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_c3da670d-d6cf-4eff-b8dd-c4655a512f22" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtWeightedAverageInterestRate"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract_592c5a7a-a05c-48e0-a5b3-6377c42cb6ad" xlink:to="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_c3da670d-d6cf-4eff-b8dd-c4655a512f22" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RisksAndUncertaintiesAbstract_ecd00f56-c2a8-43f7-be96-8755d16a8d3f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RisksAndUncertaintiesAbstract"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_edc063b4-3dd8-43d1-8c34-6faef8d0fbd8" xlink:to="loc_us-gaap_RisksAndUncertaintiesAbstract_ecd00f56-c2a8-43f7-be96-8755d16a8d3f" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_ConcentrationRiskNumberOfSupplier_a5816443-653c-47bb-b112-5c30360a36d1" xlink:href="syx-20201231.xsd#syx_ConcentrationRiskNumberOfSupplier"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RisksAndUncertaintiesAbstract_ecd00f56-c2a8-43f7-be96-8755d16a8d3f" xlink:to="loc_syx_ConcentrationRiskNumberOfSupplier_a5816443-653c-47bb-b112-5c30360a36d1" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ed3b3807-a1a8-462a-a574-866c72ba4d7d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_edc063b4-3dd8-43d1-8c34-6faef8d0fbd8" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ed3b3807-a1a8-462a-a574-866c72ba4d7d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_56c8dbcd-952a-4c4a-92fa-abaaa867196a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ed3b3807-a1a8-462a-a574-866c72ba4d7d" xlink:to="loc_us-gaap_AwardTypeAxis_56c8dbcd-952a-4c4a-92fa-abaaa867196a" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_56c8dbcd-952a-4c4a-92fa-abaaa867196a_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_56c8dbcd-952a-4c4a-92fa-abaaa867196a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_56c8dbcd-952a-4c4a-92fa-abaaa867196a_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8b910258-eef0-4d82-8c1b-7327bca813e7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_56c8dbcd-952a-4c4a-92fa-abaaa867196a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8b910258-eef0-4d82-8c1b-7327bca813e7" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_62d6f27b-9d41-4d36-8bb1-41b4a988f0a0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8b910258-eef0-4d82-8c1b-7327bca813e7" xlink:to="loc_us-gaap_EmployeeStockOptionMember_62d6f27b-9d41-4d36-8bb1-41b4a988f0a0" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_f867257f-1954-4b48-820f-6d83b16a6c6a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8b910258-eef0-4d82-8c1b-7327bca813e7" xlink:to="loc_us-gaap_RestrictedStockMember_f867257f-1954-4b48-820f-6d83b16a6c6a" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c05a2af5-b684-4605-9302-e412e2725a03" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ed3b3807-a1a8-462a-a574-866c72ba4d7d" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c05a2af5-b684-4605-9302-e412e2725a03" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c05a2af5-b684-4605-9302-e412e2725a03_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c05a2af5-b684-4605-9302-e412e2725a03" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c05a2af5-b684-4605-9302-e412e2725a03_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_774adb41-a889-4f13-ab25-ae9fc04da1f6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c05a2af5-b684-4605-9302-e412e2725a03" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_774adb41-a889-4f13-ab25-ae9fc04da1f6" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_FurnitureFixturesAndEquipmentMember_f84aadd9-1b6f-4596-8171-a37aeef606b3" xlink:href="syx-20201231.xsd#syx_FurnitureFixturesAndEquipmentMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_774adb41-a889-4f13-ab25-ae9fc04da1f6" xlink:to="loc_syx_FurnitureFixturesAndEquipmentMember_f84aadd9-1b6f-4596-8171-a37aeef606b3" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SoftwareDevelopmentMember_ce57174d-816d-43b7-ae31-8fe1180a8a62" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SoftwareDevelopmentMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_774adb41-a889-4f13-ab25-ae9fc04da1f6" xlink:to="loc_us-gaap_SoftwareDevelopmentMember_ce57174d-816d-43b7-ae31-8fe1180a8a62" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e046b38b-ce0a-4417-b67f-c253708745ae" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ed3b3807-a1a8-462a-a574-866c72ba4d7d" xlink:to="loc_srt_RangeAxis_e046b38b-ce0a-4417-b67f-c253708745ae" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e046b38b-ce0a-4417-b67f-c253708745ae_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e046b38b-ce0a-4417-b67f-c253708745ae" xlink:to="loc_srt_RangeMember_e046b38b-ce0a-4417-b67f-c253708745ae_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_acd20dd9-7bc4-4bbe-8bdb-b47ded1d0aa5" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e046b38b-ce0a-4417-b67f-c253708745ae" xlink:to="loc_srt_RangeMember_acd20dd9-7bc4-4bbe-8bdb-b47ded1d0aa5" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_8354167e-5c0e-4f4d-b1f8-0562fdbc80e1" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_acd20dd9-7bc4-4bbe-8bdb-b47ded1d0aa5" xlink:to="loc_srt_MinimumMember_8354167e-5c0e-4f4d-b1f8-0562fdbc80e1" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_a21cca15-bee7-4d59-94e1-8843eb513952" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_acd20dd9-7bc4-4bbe-8bdb-b47ded1d0aa5" xlink:to="loc_srt_MaximumMember_a21cca15-bee7-4d59-94e1-8843eb513952" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_105c09fd-b520-4c69-a974-1498668bafdc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ed3b3807-a1a8-462a-a574-866c72ba4d7d" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_105c09fd-b520-4c69-a974-1498668bafdc" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_105c09fd-b520-4c69-a974-1498668bafdc_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_105c09fd-b520-4c69-a974-1498668bafdc" xlink:to="loc_us-gaap_SegmentDomain_105c09fd-b520-4c69-a974-1498668bafdc_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a08c7c1e-9adb-4d9e-b712-69bfa41b08a7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_105c09fd-b520-4c69-a974-1498668bafdc" xlink:to="loc_us-gaap_SegmentDomain_a08c7c1e-9adb-4d9e-b712-69bfa41b08a7" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_NorthAmericanTechnologyProductsSegmentMember_d780189a-4975-4180-9d36-b9098337ea26" xlink:href="syx-20201231.xsd#syx_NorthAmericanTechnologyProductsSegmentMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a08c7c1e-9adb-4d9e-b712-69bfa41b08a7" xlink:to="loc_syx_NorthAmericanTechnologyProductsSegmentMember_d780189a-4975-4180-9d36-b9098337ea26" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/CREDITLOSSES" xlink:type="simple" xlink:href="syx-20201231.xsd#CREDITLOSSES"/>
<link:definitionLink xlink:role="http://systemax.com/role/CREDITLOSSES" xlink:type="extended" id="i1586e9eecc9b4a1f8bea3c7bf5b28900_CREDITLOSSES"/>
<link:roleRef roleURI="http://systemax.com/role/CREDITLOSSESTables" xlink:type="simple" xlink:href="syx-20201231.xsd#CREDITLOSSESTables"/>
<link:definitionLink xlink:role="http://systemax.com/role/CREDITLOSSESTables" xlink:type="extended" id="i67cf241541a445059c83fbd904a21c0f_CREDITLOSSESTables"/>
<link:roleRef roleURI="http://systemax.com/role/CREDITLOSSESDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#CREDITLOSSESDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/CREDITLOSSESDetails" xlink:type="extended" id="i130356002b7d4bef84ac2ea775aeed3b_CREDITLOSSESDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3a3cfbbc-6d5d-4faa-8112-f65ec2261b2d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_5bebe2e0-c497-4fd2-b5f9-a667f38f9755" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3a3cfbbc-6d5d-4faa-8112-f65ec2261b2d" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_5bebe2e0-c497-4fd2-b5f9-a667f38f9755" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_a0c178fa-df2f-46da-a76d-08291aedf0eb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_5bebe2e0-c497-4fd2-b5f9-a667f38f9755" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_a0c178fa-df2f-46da-a76d-08291aedf0eb" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease_889cbe95-ad45-481e-a422-a352a88e1a55" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_5bebe2e0-c497-4fd2-b5f9-a667f38f9755" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease_889cbe95-ad45-481e-a422-a352a88e1a55" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_c1438537-16ea-42b7-a4cf-9f6d09a84e73" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_5bebe2e0-c497-4fd2-b5f9-a667f38f9755" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_c1438537-16ea-42b7-a4cf-9f6d09a84e73" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_2c2944b3-0b78-44fa-9bb4-c9d4659f48a8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_dbf74cf4-8c10-4da0-b4cc-0db089464b42" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3a3cfbbc-6d5d-4faa-8112-f65ec2261b2d" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_dbf74cf4-8c10-4da0-b4cc-0db089464b42" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_1030d435-8de5-470e-b4b8-7ffe88f543ee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_dbf74cf4-8c10-4da0-b4cc-0db089464b42" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_1030d435-8de5-470e-b4b8-7ffe88f543ee" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_1030d435-8de5-470e-b4b8-7ffe88f543ee_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_1030d435-8de5-470e-b4b8-7ffe88f543ee" xlink:to="loc_us-gaap_ReceivableTypeDomain_1030d435-8de5-470e-b4b8-7ffe88f543ee_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_1f99e6a9-f9f9-4bcb-b9a6-902b78997ba8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReceivableTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_1030d435-8de5-470e-b4b8-7ffe88f543ee" xlink:to="loc_us-gaap_ReceivableTypeDomain_1f99e6a9-f9f9-4bcb-b9a6-902b78997ba8" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeAccountsReceivableMember_8542fb49-1686-412c-8fdd-e790a26f49f2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TradeAccountsReceivableMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_1f99e6a9-f9f9-4bcb-b9a6-902b78997ba8" xlink:to="loc_us-gaap_TradeAccountsReceivableMember_8542fb49-1686-412c-8fdd-e790a26f49f2" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableMember_272a29bf-fc92-436f-97b8-43deb1d30bf8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesReceivableMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_1f99e6a9-f9f9-4bcb-b9a6-902b78997ba8" xlink:to="loc_us-gaap_NotesReceivableMember_272a29bf-fc92-436f-97b8-43deb1d30bf8" xlink:type="arc" order="1"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/LEASES" xlink:type="simple" xlink:href="syx-20201231.xsd#LEASES"/>
<link:definitionLink xlink:role="http://systemax.com/role/LEASES" xlink:type="extended" id="i33bf0c66e2ea487e8310a10f49e2941f_LEASES"/>
<link:roleRef roleURI="http://systemax.com/role/LEASESTables" xlink:type="simple" xlink:href="syx-20201231.xsd#LEASESTables"/>
<link:definitionLink xlink:role="http://systemax.com/role/LEASESTables" xlink:type="extended" id="i123e86b3508c477288d426c1709c88ff_LEASESTables"/>
<link:roleRef roleURI="http://systemax.com/role/LEASESDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#LEASESDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/LEASESDetails" xlink:type="extended" id="id2fd618c0a9946719d592303f23e0e13_LEASESDetails"/>
<link:roleRef roleURI="http://systemax.com/role/LEASESLeaseExpenseDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#LEASESLeaseExpenseDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/LEASESLeaseExpenseDetails" xlink:type="extended" id="i5445d2d8447140c8858700806888efbe_LEASESLeaseExpenseDetails"/>
<link:roleRef roleURI="http://systemax.com/role/LEASESMaturitiesofLeaseLiabilitiesDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#LEASESMaturitiesofLeaseLiabilitiesDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/LEASESMaturitiesofLeaseLiabilitiesDetails" xlink:type="extended" id="ie7646e0bc0fd435cb9e30a480c4e899b_LEASESMaturitiesofLeaseLiabilitiesDetails"/>
<link:roleRef roleURI="http://systemax.com/role/REVENUE" xlink:type="simple" xlink:href="syx-20201231.xsd#REVENUE"/>
<link:definitionLink xlink:role="http://systemax.com/role/REVENUE" xlink:type="extended" id="ibcbf46b4b2fa4a42b1989f66cf1c6e2f_REVENUE"/>
<link:roleRef roleURI="http://systemax.com/role/REVENUETables" xlink:type="simple" xlink:href="syx-20201231.xsd#REVENUETables"/>
<link:definitionLink xlink:role="http://systemax.com/role/REVENUETables" xlink:type="extended" id="i3cd8a16134ac45af9e2db01337107bdc_REVENUETables"/>
<link:roleRef roleURI="http://systemax.com/role/REVENUEDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#REVENUEDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/REVENUEDetails" xlink:type="extended" id="i2a7db08826ef4779bf31fe421bb237ee_REVENUEDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_7c0435fa-6715-4529-9534-c2b578a26b3f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_e71d200c-e3ae-4b89-86ad-b41b2803a684" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_7c0435fa-6715-4529-9534-c2b578a26b3f" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_e71d200c-e3ae-4b89-86ad-b41b2803a684" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_e64d510c-9e38-43d4-96cb-f9544fdb2d98" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_7c0435fa-6715-4529-9534-c2b578a26b3f" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_e64d510c-9e38-43d4-96cb-f9544fdb2d98" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_d9aae95c-e31c-4e31-bb31-c6abec0c82f8" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e64d510c-9e38-43d4-96cb-f9544fdb2d98" xlink:to="loc_srt_ConsolidationItemsAxis_d9aae95c-e31c-4e31-bb31-c6abec0c82f8" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_d9aae95c-e31c-4e31-bb31-c6abec0c82f8_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_d9aae95c-e31c-4e31-bb31-c6abec0c82f8" xlink:to="loc_srt_ConsolidationItemsDomain_d9aae95c-e31c-4e31-bb31-c6abec0c82f8_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_f1b3ecea-6e65-46ed-b858-5ba7d1c6fd36" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_d9aae95c-e31c-4e31-bb31-c6abec0c82f8" xlink:to="loc_srt_ConsolidationItemsDomain_f1b3ecea-6e65-46ed-b858-5ba7d1c6fd36" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ReportableGeographicalComponentsMember_b18b9da5-f7bf-43fc-919c-596ca82da6b5" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ReportableGeographicalComponentsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_f1b3ecea-6e65-46ed-b858-5ba7d1c6fd36" xlink:to="loc_srt_ReportableGeographicalComponentsMember_b18b9da5-f7bf-43fc-919c-596ca82da6b5" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_bbf7abd4-d8a7-4e4c-b9c6-f293381b9cce" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementGeographicalAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e64d510c-9e38-43d4-96cb-f9544fdb2d98" xlink:to="loc_srt_StatementGeographicalAxis_bbf7abd4-d8a7-4e4c-b9c6-f293381b9cce" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_bbf7abd4-d8a7-4e4c-b9c6-f293381b9cce_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_bbf7abd4-d8a7-4e4c-b9c6-f293381b9cce" xlink:to="loc_srt_SegmentGeographicalDomain_bbf7abd4-d8a7-4e4c-b9c6-f293381b9cce_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_04b13492-431a-4393-ac46-046a1dbbe576" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_bbf7abd4-d8a7-4e4c-b9c6-f293381b9cce" xlink:to="loc_srt_SegmentGeographicalDomain_04b13492-431a-4393-ac46-046a1dbbe576" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_country_US_6e53ae0b-c220-4798-9fc2-2369f1aa8ec6" xlink:href="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd#country_US"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_04b13492-431a-4393-ac46-046a1dbbe576" xlink:to="loc_country_US_6e53ae0b-c220-4798-9fc2-2369f1aa8ec6" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_country_CA_39a1e712-716d-414c-9875-b5a864a75d5e" xlink:href="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd#country_CA"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_04b13492-431a-4393-ac46-046a1dbbe576" xlink:to="loc_country_CA_39a1e712-716d-414c-9875-b5a864a75d5e" xlink:type="arc" order="1"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/DISPOSITIONSANDSPECIALGAINSANDCHARGES" xlink:type="simple" xlink:href="syx-20201231.xsd#DISPOSITIONSANDSPECIALGAINSANDCHARGES"/>
<link:definitionLink xlink:role="http://systemax.com/role/DISPOSITIONSANDSPECIALGAINSANDCHARGES" xlink:type="extended" id="ifae8ed6fb38240c4add24e6313e33da9_DISPOSITIONSANDSPECIALGAINSANDCHARGES"/>
<link:roleRef roleURI="http://systemax.com/role/DISPOSITIONSANDSPECIALGAINSANDCHARGESTables" xlink:type="simple" xlink:href="syx-20201231.xsd#DISPOSITIONSANDSPECIALGAINSANDCHARGESTables"/>
<link:definitionLink xlink:role="http://systemax.com/role/DISPOSITIONSANDSPECIALGAINSANDCHARGESTables" xlink:type="extended" id="id66762729fe0408ea9a70c12d4de44ee_DISPOSITIONSANDSPECIALGAINSANDCHARGESTables"/>
<link:roleRef roleURI="http://systemax.com/role/DISPOSITIONSANDSPECIALGAINSANDCHARGESNarrativeDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#DISPOSITIONSANDSPECIALGAINSANDCHARGESNarrativeDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/DISPOSITIONSANDSPECIALGAINSANDCHARGESNarrativeDetails" xlink:type="extended" id="i5862da6eff964ec4a0ffd9dee67875d5_DISPOSITIONSANDSPECIALGAINSANDCHARGESNarrativeDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_587ca938-52f3-412a-89ea-442fcea991cc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_SpecialCharges_e4968db3-e1cd-41bf-8053-27c706e484e5" xlink:href="syx-20201231.xsd#syx_SpecialCharges"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_587ca938-52f3-412a-89ea-442fcea991cc" xlink:to="loc_syx_SpecialCharges_e4968db3-e1cd-41bf-8053-27c706e484e5" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_DisposalGroupIncludingDiscontinuedOperationRestitutionReceipts_4938b345-a736-4fdc-92e9-ce03c95dcc98" xlink:href="syx-20201231.xsd#syx_DisposalGroupIncludingDiscontinuedOperationRestitutionReceipts"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_587ca938-52f3-412a-89ea-442fcea991cc" xlink:to="loc_syx_DisposalGroupIncludingDiscontinuedOperationRestitutionReceipts_4938b345-a736-4fdc-92e9-ce03c95dcc98" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfessionalFees_fb4003f6-d334-48ad-b308-d6c0044d580f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProfessionalFees"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_587ca938-52f3-412a-89ea-442fcea991cc" xlink:to="loc_us-gaap_ProfessionalFees_fb4003f6-d334-48ad-b308-d6c0044d580f" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_c023f3ea-bd34-4151-b468-d3b71b4a76ab" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_587ca938-52f3-412a-89ea-442fcea991cc" xlink:to="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_c023f3ea-bd34-4151-b468-d3b71b4a76ab" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_LeaseReserveAdjustments_8b6f3ca4-1a62-4074-a04e-bb4384dfaf18" xlink:href="syx-20201231.xsd#syx_LeaseReserveAdjustments"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_587ca938-52f3-412a-89ea-442fcea991cc" xlink:to="loc_syx_LeaseReserveAdjustments_8b6f3ca4-1a62-4074-a04e-bb4384dfaf18" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_ProfessionalCostsRelatedToOngoingRestitutionProceedings_504b53a7-7322-4336-849f-9eec094e3825" xlink:href="syx-20201231.xsd#syx_ProfessionalCostsRelatedToOngoingRestitutionProceedings"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_587ca938-52f3-412a-89ea-442fcea991cc" xlink:to="loc_syx_ProfessionalCostsRelatedToOngoingRestitutionProceedings_504b53a7-7322-4336-849f-9eec094e3825" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_DisposalGroupIncludingDiscontinuedOperationVendorSettlement_14b4e75c-fb11-4cdc-9187-94f1447828d7" xlink:href="syx-20201231.xsd#syx_DisposalGroupIncludingDiscontinuedOperationVendorSettlement"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_587ca938-52f3-412a-89ea-442fcea991cc" xlink:to="loc_syx_DisposalGroupIncludingDiscontinuedOperationVendorSettlement_14b4e75c-fb11-4cdc-9187-94f1447828d7" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_SpecialChargesExpectedFutureCharges_7a516ce7-4642-49c8-9d1c-90f78aae0000" xlink:href="syx-20201231.xsd#syx_SpecialChargesExpectedFutureCharges"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_587ca938-52f3-412a-89ea-442fcea991cc" xlink:to="loc_syx_SpecialChargesExpectedFutureCharges_7a516ce7-4642-49c8-9d1c-90f78aae0000" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_BuyoutOfOutstandingLeaseObligation_6b1c8af0-cbeb-4ef9-b863-958fbf1c1eb2" xlink:href="syx-20201231.xsd#syx_BuyoutOfOutstandingLeaseObligation"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_587ca938-52f3-412a-89ea-442fcea991cc" xlink:to="loc_syx_BuyoutOfOutstandingLeaseObligation_6b1c8af0-cbeb-4ef9-b863-958fbf1c1eb2" xlink:type="arc" order="8"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d6e1e8c6-c3c2-4aef-ae5f-64760d9e6350" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_587ca938-52f3-412a-89ea-442fcea991cc" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d6e1e8c6-c3c2-4aef-ae5f-64760d9e6350" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_049ed92c-c146-42af-9784-ffc26f6e1c88" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementGeographicalAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d6e1e8c6-c3c2-4aef-ae5f-64760d9e6350" xlink:to="loc_srt_StatementGeographicalAxis_049ed92c-c146-42af-9784-ffc26f6e1c88" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_049ed92c-c146-42af-9784-ffc26f6e1c88_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_049ed92c-c146-42af-9784-ffc26f6e1c88" xlink:to="loc_srt_SegmentGeographicalDomain_049ed92c-c146-42af-9784-ffc26f6e1c88_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_f8cd24a1-b924-4c5a-b70f-cd20700bf7be" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_049ed92c-c146-42af-9784-ffc26f6e1c88" xlink:to="loc_srt_SegmentGeographicalDomain_f8cd24a1-b924-4c5a-b70f-cd20700bf7be" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_country_DE_6d583da6-ad47-425c-8bdc-3b95317ef383" xlink:href="https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd#country_DE"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_f8cd24a1-b924-4c5a-b70f-cd20700bf7be" xlink:to="loc_country_DE_6d583da6-ad47-425c-8bdc-3b95317ef383" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_f47bd0bf-cd8b-4c80-ab7b-c9fa203c9621" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementOperatingActivitiesSegmentAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d6e1e8c6-c3c2-4aef-ae5f-64760d9e6350" xlink:to="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_f47bd0bf-cd8b-4c80-ab7b-c9fa203c9621" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentOperatingActivitiesDomain_f47bd0bf-cd8b-4c80-ab7b-c9fa203c9621_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentOperatingActivitiesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_f47bd0bf-cd8b-4c80-ab7b-c9fa203c9621" xlink:to="loc_us-gaap_SegmentOperatingActivitiesDomain_f47bd0bf-cd8b-4c80-ab7b-c9fa203c9621_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentOperatingActivitiesDomain_01f11b01-28bf-4fcf-a304-9084d16311fa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentOperatingActivitiesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_f47bd0bf-cd8b-4c80-ab7b-c9fa203c9621" xlink:to="loc_us-gaap_SegmentOperatingActivitiesDomain_01f11b01-28bf-4fcf-a304-9084d16311fa" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDiscontinuedOperationsMember_16d5255d-7b4c-4280-a1f6-1b9264736fa9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDiscontinuedOperationsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentOperatingActivitiesDomain_01f11b01-28bf-4fcf-a304-9084d16311fa" xlink:to="loc_us-gaap_SegmentDiscontinuedOperationsMember_16d5255d-7b4c-4280-a1f6-1b9264736fa9" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentContinuingOperationsMember_524129e5-db97-4fe2-945b-839927fd4389" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentContinuingOperationsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentOperatingActivitiesDomain_01f11b01-28bf-4fcf-a304-9084d16311fa" xlink:to="loc_us-gaap_SegmentContinuingOperationsMember_524129e5-db97-4fe2-945b-839927fd4389" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_de2de726-012b-46cb-ab66-a540da7371b8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d6e1e8c6-c3c2-4aef-ae5f-64760d9e6350" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_de2de726-012b-46cb-ab66-a540da7371b8" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_de2de726-012b-46cb-ab66-a540da7371b8_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_de2de726-012b-46cb-ab66-a540da7371b8" xlink:to="loc_us-gaap_SegmentDomain_de2de726-012b-46cb-ab66-a540da7371b8_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_30442ccc-abf5-439f-988a-5d59fbf0ec37" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_de2de726-012b-46cb-ab66-a540da7371b8" xlink:to="loc_us-gaap_SegmentDomain_30442ccc-abf5-439f-988a-5d59fbf0ec37" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_NorthAmericanTechnologyProductsSegmentMember_b3a32653-5e26-444a-9607-90cd0c1f3352" xlink:href="syx-20201231.xsd#syx_NorthAmericanTechnologyProductsSegmentMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_30442ccc-abf5-439f-988a-5d59fbf0ec37" xlink:to="loc_syx_NorthAmericanTechnologyProductsSegmentMember_b3a32653-5e26-444a-9607-90cd0c1f3352" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_25cbcdb9-d184-4a81-9d67-35edec6c4019" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupClassificationAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d6e1e8c6-c3c2-4aef-ae5f-64760d9e6350" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_25cbcdb9-d184-4a81-9d67-35edec6c4019" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_25cbcdb9-d184-4a81-9d67-35edec6c4019_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupClassificationDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_25cbcdb9-d184-4a81-9d67-35edec6c4019" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_25cbcdb9-d184-4a81-9d67-35edec6c4019_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_93c5e978-009f-4a63-99d2-34b7c4548011" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupClassificationDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_25cbcdb9-d184-4a81-9d67-35edec6c4019" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_93c5e978-009f-4a63-99d2-34b7c4548011" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_be7559cf-8383-4c44-a94b-42332be6d539" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DiscontinuedOperationsDisposedOfBySaleMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_93c5e978-009f-4a63-99d2-34b7c4548011" xlink:to="loc_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_be7559cf-8383-4c44-a94b-42332be6d539" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_ecd11920-f09f-4b37-9910-337b1a8b5582" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d6e1e8c6-c3c2-4aef-ae5f-64760d9e6350" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_ecd11920-f09f-4b37-9910-337b1a8b5582" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_ecd11920-f09f-4b37-9910-337b1a8b5582_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_ecd11920-f09f-4b37-9910-337b1a8b5582" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_ecd11920-f09f-4b37-9910-337b1a8b5582_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_4c25fa10-d12b-4fd4-90c8-f44d99e0d292" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_ecd11920-f09f-4b37-9910-337b1a8b5582" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_4c25fa10-d12b-4fd4-90c8-f44d99e0d292" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_NorthAmericanTechnologyProductsSegmentMember_0dbe9d24-313d-4b1f-b895-25da1916fd85" xlink:href="syx-20201231.xsd#syx_NorthAmericanTechnologyProductsSegmentMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_4c25fa10-d12b-4fd4-90c8-f44d99e0d292" xlink:to="loc_syx_NorthAmericanTechnologyProductsSegmentMember_0dbe9d24-313d-4b1f-b895-25da1916fd85" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_FrenchBusinessUnitMember_71d4d0b1-3b14-445f-8470-503fda202d5a" xlink:href="syx-20201231.xsd#syx_FrenchBusinessUnitMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_4c25fa10-d12b-4fd4-90c8-f44d99e0d292" xlink:to="loc_syx_FrenchBusinessUnitMember_71d4d0b1-3b14-445f-8470-503fda202d5a" xlink:type="arc" order="1"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/DISPOSITIONSANDSPECIALGAINSANDCHARGESDiscontinuedOperationsDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#DISPOSITIONSANDSPECIALGAINSANDCHARGESDiscontinuedOperationsDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/DISPOSITIONSANDSPECIALGAINSANDCHARGESDiscontinuedOperationsDetails" xlink:type="extended" id="ibbdf5301884c4bc197a14184703f56d4_DISPOSITIONSANDSPECIALGAINSANDCHARGESDiscontinuedOperationsDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_e5da3555-dbb1-4871-aaad-aee95540902a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_e5da3555-dbb1-4871-aaad-aee95540902a" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold_54309044-430a-4fc6-96b5-77c4df6dbf6b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold_54309044-430a-4fc6-96b5-77c4df6dbf6b" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss_d6db88b2-ef44-4743-946e-06244150e1dd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGrossProfitLoss_d6db88b2-ef44-4743-946e-06244150e1dd" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense_7e07a1eb-004c-41dd-8a2a-acdec01526d9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense_7e07a1eb-004c-41dd-8a2a-acdec01526d9" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_59813b00-11a0-4f8e-af11-2718b989342a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_59813b00-11a0-4f8e-af11-2718b989342a" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_DisposalGroupIncludingDiscontinuedOperationSpecialCharges_11b50bf2-e318-436d-b789-6493b3d5b86e" xlink:href="syx-20201231.xsd#syx_DisposalGroupIncludingDiscontinuedOperationSpecialCharges"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_syx_DisposalGroupIncludingDiscontinuedOperationSpecialCharges_11b50bf2-e318-436d-b789-6493b3d5b86e" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss_f1f159d4-0559-4808-827e-cf99d2c98dd3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss_f1f159d4-0559-4808-827e-cf99d2c98dd3" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationForeignCurrencyTranslationGainsLosses_dad19e02-206e-43f1-8c25-768523c73262" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationForeignCurrencyTranslationGainsLosses"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationForeignCurrencyTranslationGainsLosses_dad19e02-206e-43f1-8c25-768523c73262" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_f13155b4-68d6-4285-a531-b29902ebe2c9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_f13155b4-68d6-4285-a531-b29902ebe2c9" xlink:type="arc" order="8"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation_ad3042c1-1254-4796-a597-161502f6ebe0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation_ad3042c1-1254-4796-a597-161502f6ebe0" xlink:type="arc" order="9"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_a2b9df0e-bd0d-412e-8b5d-1dce67cfece8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_a2b9df0e-bd0d-412e-8b5d-1dce67cfece8" xlink:type="arc" order="10"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_e4cb331a-d53b-4e92-bdd9-dfeb9991880a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_e4cb331a-d53b-4e92-bdd9-dfeb9991880a" xlink:type="arc" order="11"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare_caa74d00-a75b-46ba-8ce9-9cbad5dc794f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare_caa74d00-a75b-46ba-8ce9-9cbad5dc794f" xlink:type="arc" order="12"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_21a9dfef-3e65-4e15-8a42-15de31ea35fb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_e1fbfbe2-359f-4316-8630-58bcc52a463a" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_21a9dfef-3e65-4e15-8a42-15de31ea35fb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_9956ac77-ec98-4e02-a840-695f95e226ae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_21a9dfef-3e65-4e15-8a42-15de31ea35fb" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_9956ac77-ec98-4e02-a840-695f95e226ae" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_9956ac77-ec98-4e02-a840-695f95e226ae_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_9956ac77-ec98-4e02-a840-695f95e226ae" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_9956ac77-ec98-4e02-a840-695f95e226ae_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6acce4c3-a8ca-4a65-ab22-384ae1b0bd1d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_9956ac77-ec98-4e02-a840-695f95e226ae" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6acce4c3-a8ca-4a65-ab22-384ae1b0bd1d" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_NorthAmericanTechnologyProductsSegmentMember_74c6e588-41c7-40fa-aacd-c162d85f87ec" xlink:href="syx-20201231.xsd#syx_NorthAmericanTechnologyProductsSegmentMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6acce4c3-a8ca-4a65-ab22-384ae1b0bd1d" xlink:to="loc_syx_NorthAmericanTechnologyProductsSegmentMember_74c6e588-41c7-40fa-aacd-c162d85f87ec" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/DISPOSITIONSANDSPECIALGAINSANDCHARGESSpecialChargesDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#DISPOSITIONSANDSPECIALGAINSANDCHARGESSpecialChargesDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/DISPOSITIONSANDSPECIALGAINSANDCHARGESSpecialChargesDetails" xlink:type="extended" id="icec2b64e03b04b82b3907e4cb7604d9f_DISPOSITIONSANDSPECIALGAINSANDCHARGESSpecialChargesDetails"/>
<link:roleRef roleURI="http://systemax.com/role/GOODWILLANDINTANGIBLES" xlink:type="simple" xlink:href="syx-20201231.xsd#GOODWILLANDINTANGIBLES"/>
<link:definitionLink xlink:role="http://systemax.com/role/GOODWILLANDINTANGIBLES" xlink:type="extended" id="id9377ede40214578a3de1e4f0bca9007_GOODWILLANDINTANGIBLES"/>
<link:roleRef roleURI="http://systemax.com/role/GOODWILLANDINTANGIBLESTables" xlink:type="simple" xlink:href="syx-20201231.xsd#GOODWILLANDINTANGIBLESTables"/>
<link:definitionLink xlink:role="http://systemax.com/role/GOODWILLANDINTANGIBLESTables" xlink:type="extended" id="i24b6ab591fe6438483bc98ce6f342c9f_GOODWILLANDINTANGIBLESTables"/>
<link:roleRef roleURI="http://systemax.com/role/GOODWILLANDINTANGIBLESGoodwillandIndefiniteLivedIntangibleAssetsDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#GOODWILLANDINTANGIBLESGoodwillandIndefiniteLivedIntangibleAssetsDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/GOODWILLANDINTANGIBLESGoodwillandIndefiniteLivedIntangibleAssetsDetails" xlink:type="extended" id="i416ac043f00f406d9faeada7ec25f9b0_GOODWILLANDINTANGIBLESGoodwillandIndefiniteLivedIntangibleAssetsDetails"/>
<link:roleRef roleURI="http://systemax.com/role/GOODWILLANDINTANGIBLESDefiniteLivedIntangibleAssetsDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#GOODWILLANDINTANGIBLESDefiniteLivedIntangibleAssetsDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/GOODWILLANDINTANGIBLESDefiniteLivedIntangibleAssetsDetails" xlink:type="extended" id="ide221fca32e64715af3c4167c055b8ca_GOODWILLANDINTANGIBLESDefiniteLivedIntangibleAssetsDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_33136e14-0565-4b2f-a2ca-e8644828b671" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_f9e8ece1-3b1a-4480-8f7a-1d643973a11d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_33136e14-0565-4b2f-a2ca-e8644828b671" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_f9e8ece1-3b1a-4480-8f7a-1d643973a11d" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_20e950c4-f2bb-46ea-bac2-5c97d3ff7b9d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_33136e14-0565-4b2f-a2ca-e8644828b671" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_20e950c4-f2bb-46ea-bac2-5c97d3ff7b9d" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_66cf73db-fa8e-4d4f-bc31-032effab36cf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_33136e14-0565-4b2f-a2ca-e8644828b671" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_66cf73db-fa8e-4d4f-bc31-032effab36cf" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_73165971-7057-4705-a59a-d82ee1db92f6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_33136e14-0565-4b2f-a2ca-e8644828b671" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_73165971-7057-4705-a59a-d82ee1db92f6" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetWeightedAveragePeriodBeforeNextRenewalOrExtension_5a2b340e-5352-4298-80b8-9667700d5e44" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetWeightedAveragePeriodBeforeNextRenewalOrExtension"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_33136e14-0565-4b2f-a2ca-e8644828b671" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetWeightedAveragePeriodBeforeNextRenewalOrExtension_5a2b340e-5352-4298-80b8-9667700d5e44" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8dde90b8-b400-4d53-a43f-0cebcf810f40" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_33136e14-0565-4b2f-a2ca-e8644828b671" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8dde90b8-b400-4d53-a43f-0cebcf810f40" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a27ed896-f6aa-4410-b76d-0962a02a3253" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8dde90b8-b400-4d53-a43f-0cebcf810f40" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a27ed896-f6aa-4410-b76d-0962a02a3253" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a27ed896-f6aa-4410-b76d-0962a02a3253_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a27ed896-f6aa-4410-b76d-0962a02a3253" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a27ed896-f6aa-4410-b76d-0962a02a3253_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ee3b3e95-e0ae-420d-9ced-c52b546af4a1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a27ed896-f6aa-4410-b76d-0962a02a3253" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ee3b3e95-e0ae-420d-9ced-c52b546af4a1" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerListsMember_3e2801e6-2bf3-4128-9296-12a23786eda3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CustomerListsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ee3b3e95-e0ae-420d-9ced-c52b546af4a1" xlink:to="loc_us-gaap_CustomerListsMember_3e2801e6-2bf3-4128-9296-12a23786eda3" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternetDomainNamesMember_77b176e1-f375-485b-846d-ff8910b5b6df" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InternetDomainNamesMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ee3b3e95-e0ae-420d-9ced-c52b546af4a1" xlink:to="loc_us-gaap_InternetDomainNamesMember_77b176e1-f375-485b-846d-ff8910b5b6df" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_2399b104-9e14-4de9-a7ee-3a2ea13a289f" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_8dde90b8-b400-4d53-a43f-0cebcf810f40" xlink:to="loc_srt_RangeAxis_2399b104-9e14-4de9-a7ee-3a2ea13a289f" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2399b104-9e14-4de9-a7ee-3a2ea13a289f_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_2399b104-9e14-4de9-a7ee-3a2ea13a289f" xlink:to="loc_srt_RangeMember_2399b104-9e14-4de9-a7ee-3a2ea13a289f_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_dbf25bcb-2f0c-4ea9-867d-735f68c4b441" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_2399b104-9e14-4de9-a7ee-3a2ea13a289f" xlink:to="loc_srt_RangeMember_dbf25bcb-2f0c-4ea9-867d-735f68c4b441" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_05652852-3bdd-4bde-a35c-f7559227722b" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_dbf25bcb-2f0c-4ea9-867d-735f68c4b441" xlink:to="loc_srt_MinimumMember_05652852-3bdd-4bde-a35c-f7559227722b" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_1886a338-fc37-4c33-8588-bcad8362bbe8" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_dbf25bcb-2f0c-4ea9-867d-735f68c4b441" xlink:to="loc_srt_MaximumMember_1886a338-fc37-4c33-8588-bcad8362bbe8" xlink:type="arc" order="1"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/GOODWILLANDINTANGIBLESScheduleofAmortizationExpenseDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#GOODWILLANDINTANGIBLESScheduleofAmortizationExpenseDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/GOODWILLANDINTANGIBLESScheduleofAmortizationExpenseDetails" xlink:type="extended" id="i02bc17ebc3954a399acfcc7c1c33baba_GOODWILLANDINTANGIBLESScheduleofAmortizationExpenseDetails"/>
<link:roleRef roleURI="http://systemax.com/role/PROPERTYPLANTANDEQUIPMENT" xlink:type="simple" xlink:href="syx-20201231.xsd#PROPERTYPLANTANDEQUIPMENT"/>
<link:definitionLink xlink:role="http://systemax.com/role/PROPERTYPLANTANDEQUIPMENT" xlink:type="extended" id="i94e7603a54ca42a0af4127bf393f9288_PROPERTYPLANTANDEQUIPMENT"/>
<link:roleRef roleURI="http://systemax.com/role/PROPERTYPLANTANDEQUIPMENTTables" xlink:type="simple" xlink:href="syx-20201231.xsd#PROPERTYPLANTANDEQUIPMENTTables"/>
<link:definitionLink xlink:role="http://systemax.com/role/PROPERTYPLANTANDEQUIPMENTTables" xlink:type="extended" id="ie9c7946b266341fb87dde6ab3a25d003_PROPERTYPLANTANDEQUIPMENTTables"/>
<link:roleRef roleURI="http://systemax.com/role/PROPERTYPLANTANDEQUIPMENTScheduleofPropertyPlantandEquipmentDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#PROPERTYPLANTANDEQUIPMENTScheduleofPropertyPlantandEquipmentDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/PROPERTYPLANTANDEQUIPMENTScheduleofPropertyPlantandEquipmentDetails" xlink:type="extended" id="ie66a2cd7d6ae4eb5934178f5e0c08145_PROPERTYPLANTANDEQUIPMENTScheduleofPropertyPlantandEquipmentDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_22ba9960-a1e8-4952-99f7-50d2df297490" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_592e4300-10c0-43cb-becd-3e3b0df0e709" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_22ba9960-a1e8-4952-99f7-50d2df297490" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_592e4300-10c0-43cb-becd-3e3b0df0e709" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_e9be58c1-ac5b-4453-bc7b-b0851e94f02b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_22ba9960-a1e8-4952-99f7-50d2df297490" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_e9be58c1-ac5b-4453-bc7b-b0851e94f02b" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_e321e14a-0040-40e4-93c3-d8b1c7d5a021" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_22ba9960-a1e8-4952-99f7-50d2df297490" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_e321e14a-0040-40e4-93c3-d8b1c7d5a021" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_c5634c8f-b62f-4c90-983c-5037d108a90f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Depreciation"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_22ba9960-a1e8-4952-99f7-50d2df297490" xlink:to="loc_us-gaap_Depreciation_c5634c8f-b62f-4c90-983c-5037d108a90f" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentDisposals_230e5511-fe4d-4df7-afc2-919faca92f1f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentDisposals"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_22ba9960-a1e8-4952-99f7-50d2df297490" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentDisposals_230e5511-fe4d-4df7-afc2-919faca92f1f" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentOtherAccumulatedDepreciation_af9146d2-b57d-4c8e-b16e-0658ba9a28d8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentOtherAccumulatedDepreciation"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_22ba9960-a1e8-4952-99f7-50d2df297490" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentOtherAccumulatedDepreciation_af9146d2-b57d-4c8e-b16e-0658ba9a28d8" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_c16e9d26-4133-43ad-b434-2835a7f85bb8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_22ba9960-a1e8-4952-99f7-50d2df297490" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_c16e9d26-4133-43ad-b434-2835a7f85bb8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_0dc6a926-3a9c-4f2f-9039-8a7fc84cbb00" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_c16e9d26-4133-43ad-b434-2835a7f85bb8" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_0dc6a926-3a9c-4f2f-9039-8a7fc84cbb00" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_0dc6a926-3a9c-4f2f-9039-8a7fc84cbb00_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_0dc6a926-3a9c-4f2f-9039-8a7fc84cbb00" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_0dc6a926-3a9c-4f2f-9039-8a7fc84cbb00_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5845cca6-addf-480c-86e6-cff03498ff29" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_0dc6a926-3a9c-4f2f-9039-8a7fc84cbb00" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5845cca6-addf-480c-86e6-cff03498ff29" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandImprovementsMember_f7a8605d-ba15-41c0-8a68-1cfe7c184eac" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LandImprovementsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5845cca6-addf-480c-86e6-cff03498ff29" xlink:to="loc_us-gaap_LandImprovementsMember_f7a8605d-ba15-41c0-8a68-1cfe7c184eac" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_FurnitureAndFixturesOfficeComputerAndOtherEquipmentAndSoftwareMember_6c4e8db8-595c-4fcc-b803-e4d31a6e342a" xlink:href="syx-20201231.xsd#syx_FurnitureAndFixturesOfficeComputerAndOtherEquipmentAndSoftwareMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5845cca6-addf-480c-86e6-cff03498ff29" xlink:to="loc_syx_FurnitureAndFixturesOfficeComputerAndOtherEquipmentAndSoftwareMember_6c4e8db8-595c-4fcc-b803-e4d31a6e342a" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_a952afde-3f08-4556-9a83-d82e7485595d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LeaseholdImprovementsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5845cca6-addf-480c-86e6-cff03498ff29" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_a952afde-3f08-4556-9a83-d82e7485595d" xlink:type="arc" order="2"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/CREDITFACILITIES" xlink:type="simple" xlink:href="syx-20201231.xsd#CREDITFACILITIES"/>
<link:definitionLink xlink:role="http://systemax.com/role/CREDITFACILITIES" xlink:type="extended" id="i449e514074704f35a4e2bd622c01c077_CREDITFACILITIES"/>
<link:roleRef roleURI="http://systemax.com/role/CREDITFACILITIESDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#CREDITFACILITIESDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/CREDITFACILITIESDetails" xlink:type="extended" id="ibac6d005484f4c7da889cb7dab385f6e_CREDITFACILITIESDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_bf4963dc-5779-4a94-a58a-2ebdc1477b19" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_bf4963dc-5779-4a94-a58a-2ebdc1477b19" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_NumberOfFinancialInstitutions_0394e6f1-11ea-46e9-9bdb-3cc2ec1ecf5d" xlink:href="syx-20201231.xsd#syx_NumberOfFinancialInstitutions"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:to="loc_syx_NumberOfFinancialInstitutions_0394e6f1-11ea-46e9-9bdb-3cc2ec1ecf5d" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_58af1d6b-ff31-485e-8f60-3d7a42d8cca8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTerm"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:to="loc_us-gaap_DebtInstrumentTerm_58af1d6b-ff31-485e-8f60-3d7a42d8cca8" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_PercentageOfEligibleAccountsReceivableForBorrowings_6f4e72b1-98ed-436e-9a34-c38feec0b365" xlink:href="syx-20201231.xsd#syx_PercentageOfEligibleAccountsReceivableForBorrowings"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:to="loc_syx_PercentageOfEligibleAccountsReceivableForBorrowings_6f4e72b1-98ed-436e-9a34-c38feec0b365" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_PercentageOfInventoryAdvanceRateComputed_5a65679e-9187-46d2-9941-62a105966eab" xlink:href="syx-20201231.xsd#syx_PercentageOfInventoryAdvanceRateComputed"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:to="loc_syx_PercentageOfInventoryAdvanceRateComputed_5a65679e-9187-46d2-9941-62a105966eab" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_PercentageOfInventoryAdvanceRateOfNOVL_7bf6857a-8f96-4ac8-821f-1e7b817b49fb" xlink:href="syx-20201231.xsd#syx_PercentageOfInventoryAdvanceRateOfNOVL"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:to="loc_syx_PercentageOfInventoryAdvanceRateOfNOVL_7bf6857a-8f96-4ac8-821f-1e7b817b49fb" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_EligibleCollateralUnderTheCreditFacility_fa3a71fe-f38a-407d-beac-a0abc37ec5f8" xlink:href="syx-20201231.xsd#syx_EligibleCollateralUnderTheCreditFacility"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:to="loc_syx_EligibleCollateralUnderTheCreditFacility_fa3a71fe-f38a-407d-beac-a0abc37ec5f8" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_fe4b450d-9d42-4f00-9a40-2cfebe101925" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_fe4b450d-9d42-4f00-9a40-2cfebe101925" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_OutstandingAdvances_8ee1bd9a-dd77-4f62-b3b4-e6e4801ff48a" xlink:href="syx-20201231.xsd#syx_OutstandingAdvances"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:to="loc_syx_OutstandingAdvances_8ee1bd9a-dd77-4f62-b3b4-e6e4801ff48a" xlink:type="arc" order="8"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_d47debaa-2959-4cb0-96c7-5f7dab09eba7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_d47debaa-2959-4cb0-96c7-5f7dab09eba7" xlink:type="arc" order="9"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_e1f330f8-d246-4375-a851-b1ccf45df5be" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_4b1e6644-3851-429f-b024-cac69abdc00f" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_e1f330f8-d246-4375-a851-b1ccf45df5be" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_a67cb43e-0a50-4cb6-a1ef-ec8f937c0467" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_e1f330f8-d246-4375-a851-b1ccf45df5be" xlink:to="loc_us-gaap_CreditFacilityAxis_a67cb43e-0a50-4cb6-a1ef-ec8f937c0467" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_a67cb43e-0a50-4cb6-a1ef-ec8f937c0467_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_a67cb43e-0a50-4cb6-a1ef-ec8f937c0467" xlink:to="loc_us-gaap_CreditFacilityDomain_a67cb43e-0a50-4cb6-a1ef-ec8f937c0467_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_dcbe341a-d95f-4374-91de-8c741ce2bb6c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_a67cb43e-0a50-4cb6-a1ef-ec8f937c0467" xlink:to="loc_us-gaap_CreditFacilityDomain_dcbe341a-d95f-4374-91de-8c741ce2bb6c" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_0ff0202f-ac85-49ba-a0f5-bc5decdbb410" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_dcbe341a-d95f-4374-91de-8c741ce2bb6c" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_0ff0202f-ac85-49ba-a0f5-bc5decdbb410" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_c83eff84-eb10-48d0-9a28-b4d5580eec7f" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_e1f330f8-d246-4375-a851-b1ccf45df5be" xlink:to="loc_srt_RangeAxis_c83eff84-eb10-48d0-9a28-b4d5580eec7f" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c83eff84-eb10-48d0-9a28-b4d5580eec7f_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_c83eff84-eb10-48d0-9a28-b4d5580eec7f" xlink:to="loc_srt_RangeMember_c83eff84-eb10-48d0-9a28-b4d5580eec7f_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_df3679de-2424-4843-9b0c-3680b66381e3" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_c83eff84-eb10-48d0-9a28-b4d5580eec7f" xlink:to="loc_srt_RangeMember_df3679de-2424-4843-9b0c-3680b66381e3" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_6decfeff-4e8a-42e7-9d4d-54a8e70ffd8d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_df3679de-2424-4843-9b0c-3680b66381e3" xlink:to="loc_srt_MaximumMember_6decfeff-4e8a-42e7-9d4d-54a8e70ffd8d" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIES" xlink:type="simple" xlink:href="syx-20201231.xsd#ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIES"/>
<link:definitionLink xlink:role="http://systemax.com/role/ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIES" xlink:type="extended" id="i57a2370735fe45859b5ed72f6ddce058_ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIES"/>
<link:roleRef roleURI="http://systemax.com/role/ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIESTables" xlink:type="simple" xlink:href="syx-20201231.xsd#ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIESTables"/>
<link:definitionLink xlink:role="http://systemax.com/role/ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIESTables" xlink:type="extended" id="i80ec8e12005b46338b418cec5cb4edef_ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIESTables"/>
<link:roleRef roleURI="http://systemax.com/role/ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIESDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIESDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIESDetails" xlink:type="extended" id="i2410779638cd47918f8dc1bc567293b1_ACCRUEDEXPENSESANDOTHERCURRENTLIABILITIESDetails"/>
<link:roleRef roleURI="http://systemax.com/role/STOCKREPURCHASES" xlink:type="simple" xlink:href="syx-20201231.xsd#STOCKREPURCHASES"/>
<link:definitionLink xlink:role="http://systemax.com/role/STOCKREPURCHASES" xlink:type="extended" id="i173ccc04402d4f81921242e4418f2391_STOCKREPURCHASES"/>
<link:roleRef roleURI="http://systemax.com/role/STOCKREPURCHASESDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#STOCKREPURCHASESDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/STOCKREPURCHASESDetails" xlink:type="extended" id="ib5361a62d4f04ae8aae7c4e83865cf29_STOCKREPURCHASESDetails"/>
<link:roleRef roleURI="http://systemax.com/role/SHAREHOLDERSEQUITY" xlink:type="simple" xlink:href="syx-20201231.xsd#SHAREHOLDERSEQUITY"/>
<link:definitionLink xlink:role="http://systemax.com/role/SHAREHOLDERSEQUITY" xlink:type="extended" id="if1e0db8d7af24cf88ed7ef8a48112179_SHAREHOLDERSEQUITY"/>
<link:roleRef roleURI="http://systemax.com/role/SHAREHOLDERSEQUITYTables" xlink:type="simple" xlink:href="syx-20201231.xsd#SHAREHOLDERSEQUITYTables"/>
<link:definitionLink xlink:role="http://systemax.com/role/SHAREHOLDERSEQUITYTables" xlink:type="extended" id="iaa03bd5ab7c84de78bbc4144d015003b_SHAREHOLDERSEQUITYTables"/>
<link:roleRef roleURI="http://systemax.com/role/SHAREHOLDERSEQUITYNarrativeDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#SHAREHOLDERSEQUITYNarrativeDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/SHAREHOLDERSEQUITYNarrativeDetails" xlink:type="extended" id="i8765e0b4374d44bb889d4b46ea485144_SHAREHOLDERSEQUITYNarrativeDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_NumberOfEquityCompensationPlans_494cd392-8908-4d6f-aabc-bb2c4d516a0c" xlink:href="syx-20201231.xsd#syx_NumberOfEquityCompensationPlans"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_syx_NumberOfEquityCompensationPlans_494cd392-8908-4d6f-aabc-bb2c4d516a0c" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_ae67c988-4f05-4e84-a582-deeb23310873" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_ae67c988-4f05-4e84-a582-deeb23310873" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumNumberOfSharesPerEmployee_ad7dd4be-41c2-47ff-9290-881ee5fbb6ad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumNumberOfSharesPerEmployee"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumNumberOfSharesPerEmployee_ad7dd4be-41c2-47ff-9290-881ee5fbb6ad" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumDollarValuePerEmployee_90c3168e-0e3d-4c00-b319-9caedf759cf8" xlink:href="syx-20201231.xsd#syx_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumDollarValuePerEmployee"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_syx_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumDollarValuePerEmployee_90c3168e-0e3d-4c00-b319-9caedf759cf8" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_c5f71372-6404-4233-b7c3-d70183c1d7b0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_c5f71372-6404-4233-b7c3-d70183c1d7b0" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_72dc0354-8fc8-47b8-8ac0-78f81a43cec4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_72dc0354-8fc8-47b8-8ac0-78f81a43cec4" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_e9426e43-0310-4c36-98b1-2dee136fb535" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_e9426e43-0310-4c36-98b1-2dee136fb535" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_17b116e9-2cf1-4ba7-afac-f1326a5d7be1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensation"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_ShareBasedCompensation_17b116e9-2cf1-4ba7-afac-f1326a5d7be1" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_SharebasedCompensationArrangementByShareBasedPaymentAwardOptionsNumberOfOutstandingSharesRepriced_488e23a1-508b-4868-a3fd-85b9303b4123" xlink:href="syx-20201231.xsd#syx_SharebasedCompensationArrangementByShareBasedPaymentAwardOptionsNumberOfOutstandingSharesRepriced"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_syx_SharebasedCompensationArrangementByShareBasedPaymentAwardOptionsNumberOfOutstandingSharesRepriced_488e23a1-508b-4868-a3fd-85b9303b4123" xlink:type="arc" order="8"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_ShareBasedCompensationAccelerationOfStockOptionsDueToSaleOfBusiness_05ba0421-35f4-4fb4-8ec9-481b9ce2d1b6" xlink:href="syx-20201231.xsd#syx_ShareBasedCompensationAccelerationOfStockOptionsDueToSaleOfBusiness"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_syx_ShareBasedCompensationAccelerationOfStockOptionsDueToSaleOfBusiness_05ba0421-35f4-4fb4-8ec9-481b9ce2d1b6" xlink:type="arc" order="9"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_ca59a773-6ce2-430c-827e-2812f1ecbb68" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_ca59a773-6ce2-430c-827e-2812f1ecbb68" xlink:type="arc" order="10"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_4e1f897f-4125-4cb7-9a0b-bd14e90e5acf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_4e1f897f-4125-4cb7-9a0b-bd14e90e5acf" xlink:type="arc" order="11"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_7b0edebc-a523-4d5c-86c6-9a810460f763" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_7b0edebc-a523-4d5c-86c6-9a810460f763" xlink:type="arc" order="12"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_f702900e-dd00-4bda-bb0a-8b9cb00ae84e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_f702900e-dd00-4bda-bb0a-8b9cb00ae84e" xlink:type="arc" order="13"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_d97e9478-39d8-4232-84d3-ec792a1fd566" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_d97e9478-39d8-4232-84d3-ec792a1fd566" xlink:type="arc" order="14"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_aa932b3d-1e9c-4e25-9de8-17b13803293e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_aa932b3d-1e9c-4e25-9de8-17b13803293e" xlink:type="arc" order="15"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_4a6feaed-ac68-4c5d-8b39-64cf86065309" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_4a6feaed-ac68-4c5d-8b39-64cf86065309" xlink:type="arc" order="16"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_SharebasedCompensationArrangementBySharebasedPaymentAwardStockPlanOfferingPeriod_bad7bc8a-a1d8-461b-b6d2-5c2804ad3493" xlink:href="syx-20201231.xsd#syx_SharebasedCompensationArrangementBySharebasedPaymentAwardStockPlanOfferingPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_syx_SharebasedCompensationArrangementBySharebasedPaymentAwardStockPlanOfferingPeriod_bad7bc8a-a1d8-461b-b6d2-5c2804ad3493" xlink:type="arc" order="17"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlansMaximumSharesAvailableToPurchasePerEmployee_40b1a58b-a668-448b-8fdd-e61b9d19b4d6" xlink:href="syx-20201231.xsd#syx_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlansMaximumSharesAvailableToPurchasePerEmployee"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_syx_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlansMaximumSharesAvailableToPurchasePerEmployee_40b1a58b-a668-448b-8fdd-e61b9d19b4d6" xlink:type="arc" order="18"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_b00bb939-d268-4776-b29d-b23cd7a8b49d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_b00bb939-d268-4776-b29d-b23cd7a8b49d" xlink:type="arc" order="19"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_3cd64efb-a3ab-4780-b435-7de8344fdf18" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_3cd64efb-a3ab-4780-b435-7de8344fdf18" xlink:type="arc" order="20"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_6f7380dc-028b-450b-8296-fe5a049fc3a0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_6f7380dc-028b-450b-8296-fe5a049fc3a0" xlink:type="arc" order="21"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockPricePerShare_6d4696d3-43c3-4baf-9d32-e36e6dac5c8e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SaleOfStockPricePerShare"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_SaleOfStockPricePerShare_6d4696d3-43c3-4baf-9d32-e36e6dac5c8e" xlink:type="arc" order="22"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_70f23bb9-8dde-400c-8b72-1b86468b30ef" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_46b43185-31bd-4b2f-9969-e482b2218e8b" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_70f23bb9-8dde-400c-8b72-1b86468b30ef" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_4c6b7b2f-cad3-4c57-a107-d220724dc7b0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementOperatingActivitiesSegmentAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_70f23bb9-8dde-400c-8b72-1b86468b30ef" xlink:to="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_4c6b7b2f-cad3-4c57-a107-d220724dc7b0" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentOperatingActivitiesDomain_4c6b7b2f-cad3-4c57-a107-d220724dc7b0_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentOperatingActivitiesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_4c6b7b2f-cad3-4c57-a107-d220724dc7b0" xlink:to="loc_us-gaap_SegmentOperatingActivitiesDomain_4c6b7b2f-cad3-4c57-a107-d220724dc7b0_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentOperatingActivitiesDomain_d7b0f2ec-f331-4e10-a8f0-836458982f45" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentOperatingActivitiesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_4c6b7b2f-cad3-4c57-a107-d220724dc7b0" xlink:to="loc_us-gaap_SegmentOperatingActivitiesDomain_d7b0f2ec-f331-4e10-a8f0-836458982f45" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDiscontinuedOperationsMember_61ae50cf-40d3-48d4-a41b-94d63ac0c591" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDiscontinuedOperationsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentOperatingActivitiesDomain_d7b0f2ec-f331-4e10-a8f0-836458982f45" xlink:to="loc_us-gaap_SegmentDiscontinuedOperationsMember_61ae50cf-40d3-48d4-a41b-94d63ac0c591" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentContinuingOperationsMember_e525b02d-9ce1-4376-9468-b8957095cdfc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentContinuingOperationsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentOperatingActivitiesDomain_d7b0f2ec-f331-4e10-a8f0-836458982f45" xlink:to="loc_us-gaap_SegmentContinuingOperationsMember_e525b02d-9ce1-4376-9468-b8957095cdfc" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_fb19a77b-eee2-47f3-bdc9-65448ebc9cb9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_70f23bb9-8dde-400c-8b72-1b86468b30ef" xlink:to="loc_us-gaap_PlanNameAxis_fb19a77b-eee2-47f3-bdc9-65448ebc9cb9" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_fb19a77b-eee2-47f3-bdc9-65448ebc9cb9_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_fb19a77b-eee2-47f3-bdc9-65448ebc9cb9" xlink:to="loc_us-gaap_PlanNameDomain_fb19a77b-eee2-47f3-bdc9-65448ebc9cb9_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_3733fcd3-ef10-413f-a43f-122458e37779" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_fb19a77b-eee2-47f3-bdc9-65448ebc9cb9" xlink:to="loc_us-gaap_PlanNameDomain_3733fcd3-ef10-413f-a43f-122458e37779" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_LongTermStockIncentivePlan2010PlanMember_b8b4ae37-a40a-45d8-ba55-01ae15695b6c" xlink:href="syx-20201231.xsd#syx_LongTermStockIncentivePlan2010PlanMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_3733fcd3-ef10-413f-a43f-122458e37779" xlink:to="loc_syx_LongTermStockIncentivePlan2010PlanMember_b8b4ae37-a40a-45d8-ba55-01ae15695b6c" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_OmnibusStockIncentivePlan2020OmnibusPlanMember_91b06adb-f8ab-49f1-b698-32a0e53d6dad" xlink:href="syx-20201231.xsd#syx_OmnibusStockIncentivePlan2020OmnibusPlanMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_3733fcd3-ef10-413f-a43f-122458e37779" xlink:to="loc_syx_OmnibusStockIncentivePlan2020OmnibusPlanMember_91b06adb-f8ab-49f1-b698-32a0e53d6dad" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2018EmployeeStockPurchasePlanMember_0a131652-950f-4891-b262-16c3584245c2" xlink:href="syx-20201231.xsd#syx_A2018EmployeeStockPurchasePlanMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_3733fcd3-ef10-413f-a43f-122458e37779" xlink:to="loc_syx_A2018EmployeeStockPurchasePlanMember_0a131652-950f-4891-b262-16c3584245c2" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_55629166-e78f-46ed-a976-6fa52d10ac82" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_70f23bb9-8dde-400c-8b72-1b86468b30ef" xlink:to="loc_us-gaap_AwardTypeAxis_55629166-e78f-46ed-a976-6fa52d10ac82" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_55629166-e78f-46ed-a976-6fa52d10ac82_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_55629166-e78f-46ed-a976-6fa52d10ac82" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_55629166-e78f-46ed-a976-6fa52d10ac82_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_08224e19-d9ee-448b-b793-afa74a3b60d5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_55629166-e78f-46ed-a976-6fa52d10ac82" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_08224e19-d9ee-448b-b793-afa74a3b60d5" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_ff248219-e36a-4072-8893-66b43105ef62" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_08224e19-d9ee-448b-b793-afa74a3b60d5" xlink:to="loc_us-gaap_EmployeeStockOptionMember_ff248219-e36a-4072-8893-66b43105ef62" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_bbbb6f98-d57e-473a-a4fc-85f3eff818ee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_08224e19-d9ee-448b-b793-afa74a3b60d5" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_bbbb6f98-d57e-473a-a4fc-85f3eff818ee" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_5ab65c2d-fe13-4b8d-b8bf-f5beae814204" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_08224e19-d9ee-448b-b793-afa74a3b60d5" xlink:to="loc_us-gaap_EmployeeStockMember_5ab65c2d-fe13-4b8d-b8bf-f5beae814204" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_EmployeeStockOptionAndRestrictedStockUnitsMember_601d575e-3b6c-4771-9557-9a314a59b093" xlink:href="syx-20201231.xsd#syx_EmployeeStockOptionAndRestrictedStockUnitsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_08224e19-d9ee-448b-b793-afa74a3b60d5" xlink:to="loc_syx_EmployeeStockOptionAndRestrictedStockUnitsMember_601d575e-3b6c-4771-9557-9a314a59b093" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_50628810-bc6f-4222-bb79-233bedaff764" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_70f23bb9-8dde-400c-8b72-1b86468b30ef" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_50628810-bc6f-4222-bb79-233bedaff764" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_50628810-bc6f-4222-bb79-233bedaff764_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_50628810-bc6f-4222-bb79-233bedaff764" xlink:to="loc_us-gaap_SegmentDomain_50628810-bc6f-4222-bb79-233bedaff764_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ed18499d-f3bf-48a3-ac40-3b044cb8b1ba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_50628810-bc6f-4222-bb79-233bedaff764" xlink:to="loc_us-gaap_SegmentDomain_ed18499d-f3bf-48a3-ac40-3b044cb8b1ba" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_EuropeanTechnologyProductsSegmentMember_d99d70df-93e9-45e9-a0fc-01f9ec1ba4e1" xlink:href="syx-20201231.xsd#syx_EuropeanTechnologyProductsSegmentMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ed18499d-f3bf-48a3-ac40-3b044cb8b1ba" xlink:to="loc_syx_EuropeanTechnologyProductsSegmentMember_d99d70df-93e9-45e9-a0fc-01f9ec1ba4e1" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_214187d3-da10-4958-a69d-393ace3ba191" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_70f23bb9-8dde-400c-8b72-1b86468b30ef" xlink:to="loc_srt_TitleOfIndividualAxis_214187d3-da10-4958-a69d-393ace3ba191" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_214187d3-da10-4958-a69d-393ace3ba191_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_214187d3-da10-4958-a69d-393ace3ba191" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_214187d3-da10-4958-a69d-393ace3ba191_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_a90e647b-1344-498b-a3e4-91dc6ba45c64" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_214187d3-da10-4958-a69d-393ace3ba191" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_a90e647b-1344-498b-a3e4-91dc6ba45c64" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_DirectorMember_684e3e18-2a08-4f8c-8ad8-930e30865e75" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_DirectorMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_a90e647b-1344-498b-a3e4-91dc6ba45c64" xlink:to="loc_srt_DirectorMember_684e3e18-2a08-4f8c-8ad8-930e30865e75" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_6e98ec9b-ad6b-471c-a164-e8d5ddbff484" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_70f23bb9-8dde-400c-8b72-1b86468b30ef" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_6e98ec9b-ad6b-471c-a164-e8d5ddbff484" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_6e98ec9b-ad6b-471c-a164-e8d5ddbff484_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_6e98ec9b-ad6b-471c-a164-e8d5ddbff484" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_6e98ec9b-ad6b-471c-a164-e8d5ddbff484_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_3d02de55-c382-4002-9df2-053099430f55" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_6e98ec9b-ad6b-471c-a164-e8d5ddbff484" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_3d02de55-c382-4002-9df2-053099430f55" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_424ffdf3-0055-4915-a5a3-be9d2cdb3458" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3d02de55-c382-4002-9df2-053099430f55" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_424ffdf3-0055-4915-a5a3-be9d2cdb3458" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/SHAREHOLDERSEQUITYWeightedAverageAssumptionsUsedtoEstimateFairValueofOptionsDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#SHAREHOLDERSEQUITYWeightedAverageAssumptionsUsedtoEstimateFairValueofOptionsDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/SHAREHOLDERSEQUITYWeightedAverageAssumptionsUsedtoEstimateFairValueofOptionsDetails" xlink:type="extended" id="i24675a9566f64eb39c334dc6ab33f4d4_SHAREHOLDERSEQUITYWeightedAverageAssumptionsUsedtoEstimateFairValueofOptionsDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ca4e0553-7282-475a-81a3-c7946b900bc1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_3adb8149-2a0e-4b01-824f-cb0c7f1abae3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ca4e0553-7282-475a-81a3-c7946b900bc1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_3adb8149-2a0e-4b01-824f-cb0c7f1abae3" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_6ff71acc-acd4-4a37-8d02-b59ceb42952a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ca4e0553-7282-475a-81a3-c7946b900bc1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_6ff71acc-acd4-4a37-8d02-b59ceb42952a" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_959b3563-710b-4960-829d-c01fa7e89215" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ca4e0553-7282-475a-81a3-c7946b900bc1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_959b3563-710b-4960-829d-c01fa7e89215" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_45cbf29e-f8bd-4cdc-a832-66ec2951646c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ca4e0553-7282-475a-81a3-c7946b900bc1" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_45cbf29e-f8bd-4cdc-a832-66ec2951646c" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_695acb48-dcb0-4202-938f-ceb530599dfa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ca4e0553-7282-475a-81a3-c7946b900bc1" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_695acb48-dcb0-4202-938f-ceb530599dfa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_d3184761-0f2c-418f-b99a-d625fa177586" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_695acb48-dcb0-4202-938f-ceb530599dfa" xlink:to="loc_us-gaap_AwardTypeAxis_d3184761-0f2c-418f-b99a-d625fa177586" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d3184761-0f2c-418f-b99a-d625fa177586_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_d3184761-0f2c-418f-b99a-d625fa177586" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d3184761-0f2c-418f-b99a-d625fa177586_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_90f7e388-ea71-4e4b-8a86-c852761daa85" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_d3184761-0f2c-418f-b99a-d625fa177586" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_90f7e388-ea71-4e4b-8a86-c852761daa85" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_04c373ad-b895-4c71-994e-e392dd762332" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_90f7e388-ea71-4e4b-8a86-c852761daa85" xlink:to="loc_us-gaap_EmployeeStockOptionMember_04c373ad-b895-4c71-994e-e392dd762332" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/SHAREHOLDERSEQUITYOptionsOutstandingandExercisableDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#SHAREHOLDERSEQUITYOptionsOutstandingandExercisableDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/SHAREHOLDERSEQUITYOptionsOutstandingandExercisableDetails" xlink:type="extended" id="i26edbe37dd3f4cc3b63677a8662bf8f0_SHAREHOLDERSEQUITYOptionsOutstandingandExercisableDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b210e224-d779-488c-b745-e892547751ed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9a782364-8bee-4bad-940d-3903a8869ef1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b210e224-d779-488c-b745-e892547751ed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9a782364-8bee-4bad-940d-3903a8869ef1" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_c6d9b1b7-9cf2-4df0-a1e0-3aab80eee1eb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9a782364-8bee-4bad-940d-3903a8869ef1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_c6d9b1b7-9cf2-4df0-a1e0-3aab80eee1eb" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_c263cc18-02bd-42a6-aaf8-ba2d76dbc6b2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9a782364-8bee-4bad-940d-3903a8869ef1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_c263cc18-02bd-42a6-aaf8-ba2d76dbc6b2" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_a75f9c8f-0b3c-49e3-b022-61a102818088" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9a782364-8bee-4bad-940d-3903a8869ef1" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_a75f9c8f-0b3c-49e3-b022-61a102818088" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod_0a64593c-de3c-4f55-bf2e-3e870b35e1e0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9a782364-8bee-4bad-940d-3903a8869ef1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod_0a64593c-de3c-4f55-bf2e-3e870b35e1e0" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_2efa561e-373d-4d79-864d-da78ba552df1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_dcbd3971-35b1-450b-bf4d-dca4350826e7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9a782364-8bee-4bad-940d-3903a8869ef1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_dcbd3971-35b1-450b-bf4d-dca4350826e7" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_025fce5b-d1b5-4e1d-b969-3f0f78c2c7f2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_9a782364-8bee-4bad-940d-3903a8869ef1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_025fce5b-d1b5-4e1d-b969-3f0f78c2c7f2" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_82e8ff10-092b-4275-a469-aa9c85ad66d9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b210e224-d779-488c-b745-e892547751ed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_82e8ff10-092b-4275-a469-aa9c85ad66d9" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_34f2dd1f-2e52-48c4-a81d-fc726df6f03d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_82e8ff10-092b-4275-a469-aa9c85ad66d9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_34f2dd1f-2e52-48c4-a81d-fc726df6f03d" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_0579d3e1-56c9-4943-8745-39d370382a84" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_82e8ff10-092b-4275-a469-aa9c85ad66d9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_0579d3e1-56c9-4943-8745-39d370382a84" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_1836c6e6-7f38-402e-a687-34fc1aa31ed9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_82e8ff10-092b-4275-a469-aa9c85ad66d9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_1836c6e6-7f38-402e-a687-34fc1aa31ed9" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_6464025b-0e2b-47d6-a5eb-0f31de6de871" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_82e8ff10-092b-4275-a469-aa9c85ad66d9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice_6464025b-0e2b-47d6-a5eb-0f31de6de871" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_c6148ffc-b043-4056-b97f-6e10df11f54b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a174bc1d-b36b-41b7-b7f6-a7145cd8f4cf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b210e224-d779-488c-b745-e892547751ed" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a174bc1d-b36b-41b7-b7f6-a7145cd8f4cf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_846dda5b-8641-4362-9b5b-7a307c6cacee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a174bc1d-b36b-41b7-b7f6-a7145cd8f4cf" xlink:to="loc_us-gaap_AwardTypeAxis_846dda5b-8641-4362-9b5b-7a307c6cacee" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_846dda5b-8641-4362-9b5b-7a307c6cacee_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_846dda5b-8641-4362-9b5b-7a307c6cacee" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_846dda5b-8641-4362-9b5b-7a307c6cacee_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09d964ae-47fa-48db-a0a2-a005b4f64a25" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_846dda5b-8641-4362-9b5b-7a307c6cacee" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09d964ae-47fa-48db-a0a2-a005b4f64a25" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_26f0f579-d1e7-4e98-a09d-5d965bfe45dc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09d964ae-47fa-48db-a0a2-a005b4f64a25" xlink:to="loc_us-gaap_EmployeeStockOptionMember_26f0f579-d1e7-4e98-a09d-5d965bfe45dc" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/SHAREHOLDERSEQUITYOptionsVestedandExercisableorNonvestedthatareExpectedtoVestDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#SHAREHOLDERSEQUITYOptionsVestedandExercisableorNonvestedthatareExpectedtoVestDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/SHAREHOLDERSEQUITYOptionsVestedandExercisableorNonvestedthatareExpectedtoVestDetails" xlink:type="extended" id="i6dd9bbec5d1743b393db0355f32d37f4_SHAREHOLDERSEQUITYOptionsVestedandExercisableorNonvestedthatareExpectedtoVestDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bf8b3f85-997b-4ddd-817e-e16d98fe499d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_908008a2-0ce1-4357-9070-f13bc6e882c0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bf8b3f85-997b-4ddd-817e-e16d98fe499d" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_908008a2-0ce1-4357-9070-f13bc6e882c0" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_b979b37c-ac3a-4d78-9501-9c5af29d02fa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bf8b3f85-997b-4ddd-817e-e16d98fe499d" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_b979b37c-ac3a-4d78-9501-9c5af29d02fa" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_dbcdbe58-64d2-47e3-a6b0-63a25e614206" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bf8b3f85-997b-4ddd-817e-e16d98fe499d" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_dbcdbe58-64d2-47e3-a6b0-63a25e614206" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_6ccab2f5-1edb-48a3-b392-d9013cd690a6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bf8b3f85-997b-4ddd-817e-e16d98fe499d" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_6ccab2f5-1edb-48a3-b392-d9013cd690a6" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2_e78713ef-7d45-474d-9aa4-f864e73a2d21" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bf8b3f85-997b-4ddd-817e-e16d98fe499d" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2_e78713ef-7d45-474d-9aa4-f864e73a2d21" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue_ddbee122-fd13-4a20-9fd7-22b02057b262" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bf8b3f85-997b-4ddd-817e-e16d98fe499d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue_ddbee122-fd13-4a20-9fd7-22b02057b262" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_68ef2ba5-27db-4944-a208-3bcbde72768b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bf8b3f85-997b-4ddd-817e-e16d98fe499d" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_68ef2ba5-27db-4944-a208-3bcbde72768b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_34099860-1488-4ef9-a4e4-4244ea57d0e7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_68ef2ba5-27db-4944-a208-3bcbde72768b" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_34099860-1488-4ef9-a4e4-4244ea57d0e7" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_34099860-1488-4ef9-a4e4-4244ea57d0e7_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_34099860-1488-4ef9-a4e4-4244ea57d0e7" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_34099860-1488-4ef9-a4e4-4244ea57d0e7_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_78be6020-d344-40ed-b32c-979433669ba9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_34099860-1488-4ef9-a4e4-4244ea57d0e7" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_78be6020-d344-40ed-b32c-979433669ba9" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_RangeOneMember_48287738-6bb6-4fda-804c-4a2a11ccdd9d" xlink:href="syx-20201231.xsd#syx_RangeOneMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_78be6020-d344-40ed-b32c-979433669ba9" xlink:to="loc_syx_RangeOneMember_48287738-6bb6-4fda-804c-4a2a11ccdd9d" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_RangeTwoMember_ca1e09bb-7ed8-4106-820e-daf4dcef97a8" xlink:href="syx-20201231.xsd#syx_RangeTwoMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_78be6020-d344-40ed-b32c-979433669ba9" xlink:to="loc_syx_RangeTwoMember_ca1e09bb-7ed8-4106-820e-daf4dcef97a8" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_RangeThreeMember_a8b2e3c3-ef12-4c2c-9268-1c0d4d4d9fc7" xlink:href="syx-20201231.xsd#syx_RangeThreeMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_78be6020-d344-40ed-b32c-979433669ba9" xlink:to="loc_syx_RangeThreeMember_a8b2e3c3-ef12-4c2c-9268-1c0d4d4d9fc7" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_RangeFourMember_2dba46b1-5fe1-43ce-95d2-f3390e6ddb58" xlink:href="syx-20201231.xsd#syx_RangeFourMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_78be6020-d344-40ed-b32c-979433669ba9" xlink:to="loc_syx_RangeFourMember_2dba46b1-5fe1-43ce-95d2-f3390e6ddb58" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_RangeSevenMember_85cc34a4-7e14-413f-b0ed-f57915776d40" xlink:href="syx-20201231.xsd#syx_RangeSevenMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_78be6020-d344-40ed-b32c-979433669ba9" xlink:to="loc_syx_RangeSevenMember_85cc34a4-7e14-413f-b0ed-f57915776d40" xlink:type="arc" order="4"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/SHAREHOLDERSEQUITYUnvestedStockOptionsDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#SHAREHOLDERSEQUITYUnvestedStockOptionsDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/SHAREHOLDERSEQUITYUnvestedStockOptionsDetails" xlink:type="extended" id="ic168f9e2301543179575626dd9f6ae55_SHAREHOLDERSEQUITYUnvestedStockOptionsDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a7158ab0-0acd-406c-a3c2-7c1b9df3a21f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d1242da6-8b91-46c5-91a3-f3fcd4c3ca7e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a7158ab0-0acd-406c-a3c2-7c1b9df3a21f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d1242da6-8b91-46c5-91a3-f3fcd4c3ca7e" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_80e65fc9-9e31-4f41-a45b-3ee45f1dc7cd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d1242da6-8b91-46c5-91a3-f3fcd4c3ca7e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_80e65fc9-9e31-4f41-a45b-3ee45f1dc7cd" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_88a58ba5-9baf-4830-8918-0319a0c15c8f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d1242da6-8b91-46c5-91a3-f3fcd4c3ca7e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_88a58ba5-9baf-4830-8918-0319a0c15c8f" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_4174df5d-f063-490d-8556-d79f3a3c07e4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d1242da6-8b91-46c5-91a3-f3fcd4c3ca7e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_4174df5d-f063-490d-8556-d79f3a3c07e4" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_864e0602-96d7-4033-8843-76e2d54b274c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d1242da6-8b91-46c5-91a3-f3fcd4c3ca7e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_864e0602-96d7-4033-8843-76e2d54b274c" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_78bc0e69-9028-49f8-a4fe-eb3f2b51d733" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_dc259412-8401-4fcc-93dd-6a64542a7301" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a7158ab0-0acd-406c-a3c2-7c1b9df3a21f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_dc259412-8401-4fcc-93dd-6a64542a7301" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_552c29b9-fac9-4085-916d-c838383cf798" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_dc259412-8401-4fcc-93dd-6a64542a7301" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_552c29b9-fac9-4085-916d-c838383cf798" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_02a9965a-8de9-460d-962d-75d7a0d20c60" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_dc259412-8401-4fcc-93dd-6a64542a7301" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_02a9965a-8de9-460d-962d-75d7a0d20c60" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_87f9a631-402f-4559-80c2-154988a460f4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_dc259412-8401-4fcc-93dd-6a64542a7301" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_87f9a631-402f-4559-80c2-154988a460f4" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_13bd1784-3a6a-4828-a7cc-6f30a3f88429" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValueRollForward_dc259412-8401-4fcc-93dd-6a64542a7301" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_13bd1784-3a6a-4828-a7cc-6f30a3f88429" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_416ae63a-271d-4868-a0e1-39144f1a6d8b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b675294e-7f5c-4e63-a0d5-2ff455408e57" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a7158ab0-0acd-406c-a3c2-7c1b9df3a21f" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b675294e-7f5c-4e63-a0d5-2ff455408e57" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_fe24ee69-43b3-42c0-8286-cd71b848f5b6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b675294e-7f5c-4e63-a0d5-2ff455408e57" xlink:to="loc_us-gaap_AwardTypeAxis_fe24ee69-43b3-42c0-8286-cd71b848f5b6" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fe24ee69-43b3-42c0-8286-cd71b848f5b6_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_fe24ee69-43b3-42c0-8286-cd71b848f5b6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fe24ee69-43b3-42c0-8286-cd71b848f5b6_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8f7f9340-759b-4fa3-8527-034615b1a6a5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_fe24ee69-43b3-42c0-8286-cd71b848f5b6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8f7f9340-759b-4fa3-8527-034615b1a6a5" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_UnvestedStockOptionsMember_04ca283f-7fc5-4169-ac1c-0c162e97eb1e" xlink:href="syx-20201231.xsd#syx_UnvestedStockOptionsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8f7f9340-759b-4fa3-8527-034615b1a6a5" xlink:to="loc_syx_UnvestedStockOptionsMember_04ca283f-7fc5-4169-ac1c-0c162e97eb1e" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/SHAREHOLDERSEQUITYRestrictedStockAwardsDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#SHAREHOLDERSEQUITYRestrictedStockAwardsDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/SHAREHOLDERSEQUITYRestrictedStockAwardsDetails" xlink:type="extended" id="i78b721b718a546448ca7b4ccdacb732d_SHAREHOLDERSEQUITYRestrictedStockAwardsDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e1b49da9-5ee4-4ca9-8d63-4f1cf13d8bcc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_62229fbd-0a63-4c7d-bbdc-08f0939840bb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e1b49da9-5ee4-4ca9-8d63-4f1cf13d8bcc" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_62229fbd-0a63-4c7d-bbdc-08f0939840bb" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_273d4da0-542f-4a15-b7e0-d6e9c91a8340" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e1b49da9-5ee4-4ca9-8d63-4f1cf13d8bcc" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_273d4da0-542f-4a15-b7e0-d6e9c91a8340" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_ccc19c33-33cb-4a72-b673-72b1c7dde666" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e1b49da9-5ee4-4ca9-8d63-4f1cf13d8bcc" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_ccc19c33-33cb-4a72-b673-72b1c7dde666" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6f27f7a7-d310-43b0-ba36-a7b6807d94c3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e1b49da9-5ee4-4ca9-8d63-4f1cf13d8bcc" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6f27f7a7-d310-43b0-ba36-a7b6807d94c3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_6717037a-6fdc-44f8-b844-cdf11f4b9ef3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementOperatingActivitiesSegmentAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6f27f7a7-d310-43b0-ba36-a7b6807d94c3" xlink:to="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_6717037a-6fdc-44f8-b844-cdf11f4b9ef3" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentOperatingActivitiesDomain_6717037a-6fdc-44f8-b844-cdf11f4b9ef3_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentOperatingActivitiesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_6717037a-6fdc-44f8-b844-cdf11f4b9ef3" xlink:to="loc_us-gaap_SegmentOperatingActivitiesDomain_6717037a-6fdc-44f8-b844-cdf11f4b9ef3_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentOperatingActivitiesDomain_526a2be9-d3eb-4c14-8b3a-1c91ce07da17" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentOperatingActivitiesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_6717037a-6fdc-44f8-b844-cdf11f4b9ef3" xlink:to="loc_us-gaap_SegmentOperatingActivitiesDomain_526a2be9-d3eb-4c14-8b3a-1c91ce07da17" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDiscontinuedOperationsMember_7d01c432-8ce6-48bf-a154-8a7fa1d01900" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDiscontinuedOperationsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentOperatingActivitiesDomain_526a2be9-d3eb-4c14-8b3a-1c91ce07da17" xlink:to="loc_us-gaap_SegmentDiscontinuedOperationsMember_7d01c432-8ce6-48bf-a154-8a7fa1d01900" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_fa9280d1-a094-4401-98a3-d007c2e51a6b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6f27f7a7-d310-43b0-ba36-a7b6807d94c3" xlink:to="loc_us-gaap_PlanNameAxis_fa9280d1-a094-4401-98a3-d007c2e51a6b" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_fa9280d1-a094-4401-98a3-d007c2e51a6b_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_fa9280d1-a094-4401-98a3-d007c2e51a6b" xlink:to="loc_us-gaap_PlanNameDomain_fa9280d1-a094-4401-98a3-d007c2e51a6b_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_4b82d479-6e8f-4c52-9f7e-9dce668ac4fd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_fa9280d1-a094-4401-98a3-d007c2e51a6b" xlink:to="loc_us-gaap_PlanNameDomain_4b82d479-6e8f-4c52-9f7e-9dce668ac4fd" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_LongTermStockIncentivePlan2010PlanMember_a1be484f-7f0d-481d-8b2c-345ef1628363" xlink:href="syx-20201231.xsd#syx_LongTermStockIncentivePlan2010PlanMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_4b82d479-6e8f-4c52-9f7e-9dce668ac4fd" xlink:to="loc_syx_LongTermStockIncentivePlan2010PlanMember_a1be484f-7f0d-481d-8b2c-345ef1628363" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_5a35b6eb-8c72-48ff-a93f-bf544ef54939" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6f27f7a7-d310-43b0-ba36-a7b6807d94c3" xlink:to="loc_us-gaap_AwardTypeAxis_5a35b6eb-8c72-48ff-a93f-bf544ef54939" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5a35b6eb-8c72-48ff-a93f-bf544ef54939_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_5a35b6eb-8c72-48ff-a93f-bf544ef54939" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5a35b6eb-8c72-48ff-a93f-bf544ef54939_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_06384941-a4f0-46fa-ad5f-e3a741f4f4f6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_5a35b6eb-8c72-48ff-a93f-bf544ef54939" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_06384941-a4f0-46fa-ad5f-e3a741f4f4f6" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_5c13a963-d6f7-4943-a079-0c91fcfffe05" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_06384941-a4f0-46fa-ad5f-e3a741f4f4f6" xlink:to="loc_us-gaap_RestrictedStockMember_5c13a963-d6f7-4943-a079-0c91fcfffe05" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateAxis_da1c0482-02e7-456c-ae10-aa042ca2f12e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardDateAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6f27f7a7-d310-43b0-ba36-a7b6807d94c3" xlink:to="loc_us-gaap_AwardDateAxis_da1c0482-02e7-456c-ae10-aa042ca2f12e" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateDomain_da1c0482-02e7-456c-ae10-aa042ca2f12e_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardDateDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardDateAxis_da1c0482-02e7-456c-ae10-aa042ca2f12e" xlink:to="loc_us-gaap_AwardDateDomain_da1c0482-02e7-456c-ae10-aa042ca2f12e_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardDateDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardDateAxis_da1c0482-02e7-456c-ae10-aa042ca2f12e" xlink:to="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2012Member_1dc8dd39-9cde-4031-b6e7-288fc903dc65" xlink:href="syx-20201231.xsd#syx_A2012Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:to="loc_syx_A2012Member_1dc8dd39-9cde-4031-b6e7-288fc903dc65" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2017TrancheOneMember_cb3d1ea9-840f-44bd-9b46-57e800cc7a9c" xlink:href="syx-20201231.xsd#syx_A2017TrancheOneMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:to="loc_syx_A2017TrancheOneMember_cb3d1ea9-840f-44bd-9b46-57e800cc7a9c" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2016Member_39fca56c-2758-4177-894a-f50b8b43ec4d" xlink:href="syx-20201231.xsd#syx_A2016Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:to="loc_syx_A2016Member_39fca56c-2758-4177-894a-f50b8b43ec4d" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2018Member_0071a6c6-7ac8-4094-91cf-df3032574f35" xlink:href="syx-20201231.xsd#syx_A2018Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:to="loc_syx_A2018Member_0071a6c6-7ac8-4094-91cf-df3032574f35" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2010Member_13a3770e-f7a7-4467-8823-61b8ab747ebc" xlink:href="syx-20201231.xsd#syx_A2010Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:to="loc_syx_A2010Member_13a3770e-f7a7-4467-8823-61b8ab747ebc" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2011Member_a67c46c9-7551-46a7-8d7a-f5c9f28cb4fb" xlink:href="syx-20201231.xsd#syx_A2011Member"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:to="loc_syx_A2011Member_a67c46c9-7551-46a7-8d7a-f5c9f28cb4fb" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2017TrancheTwoMember_1717a46d-7731-41db-9c02-64b5f2948c03" xlink:href="syx-20201231.xsd#syx_A2017TrancheTwoMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:to="loc_syx_A2017TrancheTwoMember_1717a46d-7731-41db-9c02-64b5f2948c03" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2019TrancheOneMember_6fe85234-c259-47d2-bb20-db7cb9ff7534" xlink:href="syx-20201231.xsd#syx_A2019TrancheOneMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:to="loc_syx_A2019TrancheOneMember_6fe85234-c259-47d2-bb20-db7cb9ff7534" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2019TrancheTwoMember_603da07f-a7b6-4241-8df0-295d208611d3" xlink:href="syx-20201231.xsd#syx_A2019TrancheTwoMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:to="loc_syx_A2019TrancheTwoMember_603da07f-a7b6-4241-8df0-295d208611d3" xlink:type="arc" order="8"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2020TrancheOneMember_0b7f3539-c7ed-4d0f-a13b-ef48de0f9cc2" xlink:href="syx-20201231.xsd#syx_A2020TrancheOneMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:to="loc_syx_A2020TrancheOneMember_0b7f3539-c7ed-4d0f-a13b-ef48de0f9cc2" xlink:type="arc" order="9"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_A2020TrancheTwoMember_2fe3045d-2db1-42b8-9aa0-ed49df3cc077" xlink:href="syx-20201231.xsd#syx_A2020TrancheTwoMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_ad3dc7bf-3891-4e36-8b45-642d972be8ff" xlink:to="loc_syx_A2020TrancheTwoMember_2fe3045d-2db1-42b8-9aa0-ed49df3cc077" xlink:type="arc" order="10"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/SHAREHOLDERSEQUITYUnvestedRestrictedStockDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#SHAREHOLDERSEQUITYUnvestedRestrictedStockDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/SHAREHOLDERSEQUITYUnvestedRestrictedStockDetails" xlink:type="extended" id="i64ad99d913594a6e83b51e15571706bb_SHAREHOLDERSEQUITYUnvestedRestrictedStockDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_45a70f31-cc73-413e-b5ba-c90f8fc68d83" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c3c5ec50-bb76-4775-bd9e-c64dcaa7321c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_45a70f31-cc73-413e-b5ba-c90f8fc68d83" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c3c5ec50-bb76-4775-bd9e-c64dcaa7321c" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_c23726e3-1e4a-4eb9-b07d-73bb6823dea2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c3c5ec50-bb76-4775-bd9e-c64dcaa7321c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_c23726e3-1e4a-4eb9-b07d-73bb6823dea2" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_a909b165-7427-49a1-860a-d10812034b72" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c3c5ec50-bb76-4775-bd9e-c64dcaa7321c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_a909b165-7427-49a1-860a-d10812034b72" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_48e45c75-bc7d-4814-aefb-923f9d609141" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c3c5ec50-bb76-4775-bd9e-c64dcaa7321c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_48e45c75-bc7d-4814-aefb-923f9d609141" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_d76a478b-ac98-487a-8936-6cc222380e85" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c3c5ec50-bb76-4775-bd9e-c64dcaa7321c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_d76a478b-ac98-487a-8936-6cc222380e85" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_6c7d728a-dc00-4e77-9789-fb69a4cf32b5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_419e1e56-da6e-43f6-bab8-da9567dc4c3c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_45a70f31-cc73-413e-b5ba-c90f8fc68d83" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_419e1e56-da6e-43f6-bab8-da9567dc4c3c" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_a5449cf3-fe00-4f2e-bf50-7da882a964fd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_419e1e56-da6e-43f6-bab8-da9567dc4c3c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_a5449cf3-fe00-4f2e-bf50-7da882a964fd" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_f60da450-452a-4d74-b701-e8a9648ba08a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_419e1e56-da6e-43f6-bab8-da9567dc4c3c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_f60da450-452a-4d74-b701-e8a9648ba08a" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_250aafae-d70d-484a-8b8e-16fb45a28a85" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_419e1e56-da6e-43f6-bab8-da9567dc4c3c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_250aafae-d70d-484a-8b8e-16fb45a28a85" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_8736c533-fc1b-47ff-b808-bf6cba5bb3b0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_419e1e56-da6e-43f6-bab8-da9567dc4c3c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_8736c533-fc1b-47ff-b808-bf6cba5bb3b0" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_46831124-2ef1-431c-8990-c404ac77dce4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5ba938cc-00bc-4f79-9f8d-35f0ecc16e27" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_45a70f31-cc73-413e-b5ba-c90f8fc68d83" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5ba938cc-00bc-4f79-9f8d-35f0ecc16e27" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_2e0ef7fe-2d57-4c08-b4c2-0b4a574c8cdf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5ba938cc-00bc-4f79-9f8d-35f0ecc16e27" xlink:to="loc_us-gaap_AwardTypeAxis_2e0ef7fe-2d57-4c08-b4c2-0b4a574c8cdf" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2e0ef7fe-2d57-4c08-b4c2-0b4a574c8cdf_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_2e0ef7fe-2d57-4c08-b4c2-0b4a574c8cdf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2e0ef7fe-2d57-4c08-b4c2-0b4a574c8cdf_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1f90ca8e-9a3d-4abc-b7f0-7e817151fddf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_2e0ef7fe-2d57-4c08-b4c2-0b4a574c8cdf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1f90ca8e-9a3d-4abc-b7f0-7e817151fddf" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_0a7b425a-4f01-40f6-a7fa-e84d21c2afe0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1f90ca8e-9a3d-4abc-b7f0-7e817151fddf" xlink:to="loc_us-gaap_RestrictedStockMember_0a7b425a-4f01-40f6-a7fa-e84d21c2afe0" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/INCOMETAXES" xlink:type="simple" xlink:href="syx-20201231.xsd#INCOMETAXES"/>
<link:definitionLink xlink:role="http://systemax.com/role/INCOMETAXES" xlink:type="extended" id="i739c858478e847ad811404d1ca1966dc_INCOMETAXES"/>
<link:roleRef roleURI="http://systemax.com/role/INCOMETAXESTables" xlink:type="simple" xlink:href="syx-20201231.xsd#INCOMETAXESTables"/>
<link:definitionLink xlink:role="http://systemax.com/role/INCOMETAXESTables" xlink:type="extended" id="i954f5e405f6c456da333655a391f21f5_INCOMETAXESTables"/>
<link:roleRef roleURI="http://systemax.com/role/INCOMETAXESIncomeLossfromContinuingOperationsBeforeIncomeTaxesDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#INCOMETAXESIncomeLossfromContinuingOperationsBeforeIncomeTaxesDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/INCOMETAXESIncomeLossfromContinuingOperationsBeforeIncomeTaxesDetails" xlink:type="extended" id="ia93c87282d2444a08fb5dbbf41f86a87_INCOMETAXESIncomeLossfromContinuingOperationsBeforeIncomeTaxesDetails"/>
<link:roleRef roleURI="http://systemax.com/role/INCOMETAXESBenefitProvisionforIncomeTaxesDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#INCOMETAXESBenefitProvisionforIncomeTaxesDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/INCOMETAXESBenefitProvisionforIncomeTaxesDetails" xlink:type="extended" id="icc11b5db239f4905a0c9187ebc97d096_INCOMETAXESBenefitProvisionforIncomeTaxesDetails"/>
<link:roleRef roleURI="http://systemax.com/role/INCOMETAXESNarrativeDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#INCOMETAXESNarrativeDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/INCOMETAXESNarrativeDetails" xlink:type="extended" id="i72c0126f398244359be3c09c65f8a865_INCOMETAXESNarrativeDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowanceLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationTaxExpenseBenefitFromProvisionForGainLossOnDisposal_b837b228-27e7-464d-8cc8-4ff0a5f2beee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DiscontinuedOperationTaxExpenseBenefitFromProvisionForGainLossOnDisposal"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_us-gaap_DiscontinuedOperationTaxExpenseBenefitFromProvisionForGainLossOnDisposal_b837b228-27e7-464d-8cc8-4ff0a5f2beee" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_OperatingLossCarryforwardsUtilizedInPeriod_7fcd8820-d354-4268-acb3-72691f0cc834" xlink:href="syx-20201231.xsd#syx_OperatingLossCarryforwardsUtilizedInPeriod"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_syx_OperatingLossCarryforwardsUtilizedInPeriod_7fcd8820-d354-4268-acb3-72691f0cc834" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_57d40395-51f2-4ac7-9696-d7b476466dc6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLossCarryforwards"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_us-gaap_OperatingLossCarryforwards_57d40395-51f2-4ac7-9696-d7b476466dc6" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardAmount_079f19f8-78ac-418c-9f5f-d27f903162d6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxCreditCarryforwardAmount"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_us-gaap_TaxCreditCarryforwardAmount_079f19f8-78ac-418c-9f5f-d27f903162d6" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsValuationAllowance_c029ba18-cd50-4a2c-add5-5b3f07fa3edd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_us-gaap_DeferredTaxAssetsValuationAllowance_c029ba18-cd50-4a2c-add5-5b3f07fa3edd" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsValuationAllowance_6657ab7b-1bb9-44fa-8e62-17b33846a0fd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLossCarryforwardsValuationAllowance"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_us-gaap_OperatingLossCarryforwardsValuationAllowance_6657ab7b-1bb9-44fa-8e62-17b33846a0fd" xlink:type="arc" order="5"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_OperatingLossCarryforwardsValuationAllowanceDeductibilityOfStateAndForeignTemporaryTaxDifferences_e07994bc-4d8d-4464-9710-6677080e4075" xlink:href="syx-20201231.xsd#syx_OperatingLossCarryforwardsValuationAllowanceDeductibilityOfStateAndForeignTemporaryTaxDifferences"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_syx_OperatingLossCarryforwardsValuationAllowanceDeductibilityOfStateAndForeignTemporaryTaxDifferences_e07994bc-4d8d-4464-9710-6677080e4075" xlink:type="arc" order="6"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardValuationAllowance_ed935f7d-afa2-45df-9978-6549834d64dd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxCreditCarryforwardValuationAllowance"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_us-gaap_TaxCreditCarryforwardValuationAllowance_ed935f7d-afa2-45df-9978-6549834d64dd" xlink:type="arc" order="7"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UndistributedEarningsOfForeignSubsidiaries_1a863e79-207c-4e3c-92c5-e7974f644040" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UndistributedEarningsOfForeignSubsidiaries"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_us-gaap_UndistributedEarningsOfForeignSubsidiaries_1a863e79-207c-4e3c-92c5-e7974f644040" xlink:type="arc" order="8"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUncertainTaxPositionsCurrent_eb998d81-d853-4435-8f33-3512f595979d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilityForUncertainTaxPositionsCurrent"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_us-gaap_LiabilityForUncertainTaxPositionsCurrent_eb998d81-d853-4435-8f33-3512f595979d" xlink:type="arc" order="9"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_b077df46-1a68-4f55-bdae-a3ba275de141" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_b077df46-1a68-4f55-bdae-a3ba275de141" xlink:type="arc" order="10"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowanceTable_fdd35e2b-53b9-415a-bf18-b344ceefa226" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowanceTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ValuationAllowanceLineItems_8327e5ec-5aea-426d-96b8-10e7721793de" xlink:to="loc_us-gaap_ValuationAllowanceTable_fdd35e2b-53b9-415a-bf18-b344ceefa226" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_b702e090-c636-4d8c-a5a4-4ea5fa545e5e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ValuationAllowanceTable_fdd35e2b-53b9-415a-bf18-b344ceefa226" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_b702e090-c636-4d8c-a5a4-4ea5fa545e5e" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_b702e090-c636-4d8c-a5a4-4ea5fa545e5e_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_b702e090-c636-4d8c-a5a4-4ea5fa545e5e" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_b702e090-c636-4d8c-a5a4-4ea5fa545e5e_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_4f570fd2-4515-46f8-b0ac-736ba85fd01d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_b702e090-c636-4d8c-a5a4-4ea5fa545e5e" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_4f570fd2-4515-46f8-b0ac-736ba85fd01d" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_16edfe90-faed-41f9-9de9-934d2e870ec7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_4f570fd2-4515-46f8-b0ac-736ba85fd01d" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_16edfe90-faed-41f9-9de9-934d2e870ec7" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCountryMember_eb62e691-bee2-4349-8df0-03552d1bf44a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeignCountryMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_4f570fd2-4515-46f8-b0ac-736ba85fd01d" xlink:to="loc_us-gaap_ForeignCountryMember_eb62e691-bee2-4349-8df0-03552d1bf44a" xlink:type="arc" order="1"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/INCOMETAXESReconciliationBetweenIncomeTaxExpenseandComputedIncomeTaxExpenseDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#INCOMETAXESReconciliationBetweenIncomeTaxExpenseandComputedIncomeTaxExpenseDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/INCOMETAXESReconciliationBetweenIncomeTaxExpenseandComputedIncomeTaxExpenseDetails" xlink:type="extended" id="ic6d6a842313d48e2bc92d786ab64be92_INCOMETAXESReconciliationBetweenIncomeTaxExpenseandComputedIncomeTaxExpenseDetails"/>
<link:roleRef roleURI="http://systemax.com/role/INCOMETAXESDeferredTaxAssetsandLiabilitiesDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#INCOMETAXESDeferredTaxAssetsandLiabilitiesDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/INCOMETAXESDeferredTaxAssetsandLiabilitiesDetails" xlink:type="extended" id="i88b2f901b58141bab72a455faeb2c451_INCOMETAXESDeferredTaxAssetsandLiabilitiesDetails"/>
<link:roleRef roleURI="http://systemax.com/role/COMMITMENTSCONTINGENCIESANDOTHERMATTERS" xlink:type="simple" xlink:href="syx-20201231.xsd#COMMITMENTSCONTINGENCIESANDOTHERMATTERS"/>
<link:definitionLink xlink:role="http://systemax.com/role/COMMITMENTSCONTINGENCIESANDOTHERMATTERS" xlink:type="extended" id="i6502f19a00f44fb286cff4d652ae6f2d_COMMITMENTSCONTINGENCIESANDOTHERMATTERS"/>
<link:roleRef roleURI="http://systemax.com/role/COMMITMENTSCONTINGENCIESANDOTHERMATTERSNarrativeDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#COMMITMENTSCONTINGENCIESANDOTHERMATTERSNarrativeDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/COMMITMENTSCONTINGENCIESANDOTHERMATTERSNarrativeDetails" xlink:type="extended" id="i5c4766cd04074758bb7441de9bd4fda7_COMMITMENTSCONTINGENCIESANDOTHERMATTERSNarrativeDetails"/>
<link:roleRef roleURI="http://systemax.com/role/SUBSEQUENTEVENT" xlink:type="simple" xlink:href="syx-20201231.xsd#SUBSEQUENTEVENT"/>
<link:definitionLink xlink:role="http://systemax.com/role/SUBSEQUENTEVENT" xlink:type="extended" id="iec968ce33d8743e88e6ccbe67a5a978c_SUBSEQUENTEVENT"/>
<link:roleRef roleURI="http://systemax.com/role/SUBSEQUENTEVENTDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#SUBSEQUENTEVENTDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/SUBSEQUENTEVENTDetails" xlink:type="extended" id="icfde039b09f14b629c607be4e5dd3af8_SUBSEQUENTEVENTDetails">
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_ebd3d231-e47c-43e8-8725-3a3a60f0e7d9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_syx_DisposalGroupIncludingDiscontinuedOperationRestitutionReceipts_aff21766-82d3-498b-ad95-fa7418aafb23" xlink:href="syx-20201231.xsd#syx_DisposalGroupIncludingDiscontinuedOperationRestitutionReceipts"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_ebd3d231-e47c-43e8-8725-3a3a60f0e7d9" xlink:to="loc_syx_DisposalGroupIncludingDiscontinuedOperationRestitutionReceipts_aff21766-82d3-498b-ad95-fa7418aafb23" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfessionalFees_b14eae42-c1cd-4896-91af-f61fa11ba81b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProfessionalFees"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_ebd3d231-e47c-43e8-8725-3a3a60f0e7d9" xlink:to="loc_us-gaap_ProfessionalFees_b14eae42-c1cd-4896-91af-f61fa11ba81b" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_c33d6dcc-454a-4fcc-8f12-10a5bdda9f6e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_ebd3d231-e47c-43e8-8725-3a3a60f0e7d9" xlink:to="loc_us-gaap_SubsequentEventTable_c33d6dcc-454a-4fcc-8f12-10a5bdda9f6e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_3a66d182-5306-4efb-b261-f273d7170460" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_c33d6dcc-454a-4fcc-8f12-10a5bdda9f6e" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_3a66d182-5306-4efb-b261-f273d7170460" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_3a66d182-5306-4efb-b261-f273d7170460_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_3a66d182-5306-4efb-b261-f273d7170460" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_3a66d182-5306-4efb-b261-f273d7170460_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_a7d5465d-4873-4aad-b943-0615302ac920" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_3a66d182-5306-4efb-b261-f273d7170460" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_a7d5465d-4873-4aad-b943-0615302ac920" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_2d1badca-6376-4ba0-9652-1558b8556840" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_a7d5465d-4873-4aad-b943-0615302ac920" xlink:to="loc_us-gaap_SubsequentEventMember_2d1badca-6376-4ba0-9652-1558b8556840" xlink:type="arc" order="0"/>
</link:definitionLink>
<link:roleRef roleURI="http://systemax.com/role/QUARTERLYFINANCIALDATAUNAUDITED" xlink:type="simple" xlink:href="syx-20201231.xsd#QUARTERLYFINANCIALDATAUNAUDITED"/>
<link:definitionLink xlink:role="http://systemax.com/role/QUARTERLYFINANCIALDATAUNAUDITED" xlink:type="extended" id="i048d0ec791204435b7b67a87bed257aa_QUARTERLYFINANCIALDATAUNAUDITED"/>
<link:roleRef roleURI="http://systemax.com/role/QUARTERLYFINANCIALDATAUNAUDITEDTables" xlink:type="simple" xlink:href="syx-20201231.xsd#QUARTERLYFINANCIALDATAUNAUDITEDTables"/>
<link:definitionLink xlink:role="http://systemax.com/role/QUARTERLYFINANCIALDATAUNAUDITEDTables" xlink:type="extended" id="i753e59ce47cc486bba8209ee4feeeab9_QUARTERLYFINANCIALDATAUNAUDITEDTables"/>
<link:roleRef roleURI="http://systemax.com/role/QUARTERLYFINANCIALDATAUNAUDITEDDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#QUARTERLYFINANCIALDATAUNAUDITEDDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/QUARTERLYFINANCIALDATAUNAUDITEDDetails" xlink:type="extended" id="id3d7cc78c3e842c5ac8575aae91ec551_QUARTERLYFINANCIALDATAUNAUDITEDDetails"/>
<link:roleRef roleURI="http://systemax.com/role/SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTS" xlink:type="simple" xlink:href="syx-20201231.xsd#SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTS"/>
<link:definitionLink xlink:role="http://systemax.com/role/SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTS" xlink:type="extended" id="i6c6625218c5e45119fe1c8038a0dcbcc_SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTS"/>
<link:roleRef roleURI="http://systemax.com/role/SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTSDetails" xlink:type="simple" xlink:href="syx-20201231.xsd#SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTSDetails"/>
<link:definitionLink xlink:role="http://systemax.com/role/SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTSDetails" xlink:type="extended" id="i8c35aebb5e9942808cd380cf7b07b267_SCHEDULEIIVALUATIONANDQUALIFYINGACCOUNTSDetails">
<link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_62440b88-3c80-4617-a82e-99d5a1cfd652" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ValuationAndQualifyingAccountsDisclosureLineItems"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_97815f02-0dde-4b40-b0b3-2bc8e707ee9d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_62440b88-3c80-4617-a82e-99d5a1cfd652" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_97815f02-0dde-4b40-b0b3-2bc8e707ee9d" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_0a58eec4-ff21-4f96-92f2-94ee05732aff" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_97815f02-0dde-4b40-b0b3-2bc8e707ee9d" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesBalance_0a58eec4-ff21-4f96-92f2-94ee05732aff" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_a10ee01f-3ccf-48b1-af8f-0cb00fb2c4c6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_97815f02-0dde-4b40-b0b3-2bc8e707ee9d" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_a10ee01f-3ccf-48b1-af8f-0cb00fb2c4c6" xlink:type="arc" order="2"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDeductions_087d85bf-20ac-44ba-a080-5ebede033248" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDeductions"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_97815f02-0dde-4b40-b0b3-2bc8e707ee9d" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDeductions_087d85bf-20ac-44ba-a080-5ebede033248" xlink:type="arc" order="3"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_4ed915ab-79bd-4539-9c51-29882dc7f046" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableRollforward_97815f02-0dde-4b40-b0b3-2bc8e707ee9d" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_4ed915ab-79bd-4539-9c51-29882dc7f046" xlink:type="arc" order="4"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_e915ca0c-6e63-4a4b-b794-64202a7b66dc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
<link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_c9bd3709-e345-4b11-9923-7eadc4c16b4a" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ValuationAndQualifyingAccountsDisclosureTable"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_62440b88-3c80-4617-a82e-99d5a1cfd652" xlink:to="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_c9bd3709-e345-4b11-9923-7eadc4c16b4a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_288726d4-874c-4d0c-b809-4eb7ae0ce339" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_c9bd3709-e345-4b11-9923-7eadc4c16b4a" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_288726d4-874c-4d0c-b809-4eb7ae0ce339" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_288726d4-874c-4d0c-b809-4eb7ae0ce339_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_288726d4-874c-4d0c-b809-4eb7ae0ce339" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_288726d4-874c-4d0c-b809-4eb7ae0ce339_default" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_4eddd8d6-3270-41c6-993c-1b3e9fc591a0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_288726d4-874c-4d0c-b809-4eb7ae0ce339" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_4eddd8d6-3270-41c6-993c-1b3e9fc591a0" xlink:type="arc" order="1"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForCreditLossMember_729eaf03-4434-4d4f-ab67-0c62c08d65c6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllowanceForCreditLossMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_4eddd8d6-3270-41c6-993c-1b3e9fc591a0" xlink:to="loc_us-gaap_AllowanceForCreditLossMember_729eaf03-4434-4d4f-ab67-0c62c08d65c6" xlink:type="arc" order="0"/>
<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_5df84a5c-6069-427e-a67a-732ec4c1c8af" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember"/>
<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_4eddd8d6-3270-41c6-993c-1b3e9fc591a0" xlink:to="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_5df84a5c-6069-427e-a67a-732ec4c1c8af" xlink:type="arc" order="1"/>
</link:definitionLink>
</link:linkbase>


17 Previous Filings that this Filing References

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

10/30/20  Global Industrial Co.             10-Q        9/30/20   47:4.1M
 7/31/20  Global Industrial Co.             10-Q        6/30/20   48:17M
 4/22/20  Global Industrial Co.             DEF 14A     4/22/20    1:1.4M
 3/13/20  Global Industrial Co.             10-K       12/31/19   82:9M
 8/06/19  Global Industrial Co.             10-Q        6/30/19   44:3.5M
 3/14/19  Global Industrial Co.             10-K       12/31/18   85:10M
11/02/18  Global Industrial Co.             DEF 14A    12/17/18    1:379K
12/16/16  Global Industrial Co.             8-K:1,2,9  12/14/16    2:99K                                    Broadridge Fin’l So… Inc
11/03/16  Global Industrial Co.             8-K:1,2,5,910/28/16    3:1.1M                                   Broadridge Fin’l So… Inc
 5/18/15  Global Industrial Co.             DEFA14A     5/18/15    1:90K                                    Broadridge Fin’l So… Inc
 3/13/15  Global Industrial Co.             10-K       12/31/14   70:11M                                    Broadridge Fin’l So… Inc
 5/08/12  Global Industrial Co.             10-Q        3/31/12   30:2.7M
 4/29/10  Global Industrial Co.             DEF 14A     6/11/10    1:744K                                   Kramer Levin Naf… LLP/FA
 3/13/08  Global Industrial Co.             10-K       12/31/07   11:2.2M                                   Toppan Merrill/FA
 3/13/08  Global Industrial Co.             8-K:2,5,9   3/03/08    3:175K                                   Kramer Levin Naf… LLP/FA
 8/29/06  Global Industrial Co.             10-K       12/31/05   13:1.2M                                   Stroock & Stro… Lavan/FA
 6/17/99  Global Industrial Co.             8-K:5,7     5/18/99    2:4K                                     Stroock & Stro… Lavan/FA
Top
Filing Submission 0000945114-21-000010   –   Alternative Formats (Word / Rich Text, HTML, Plain Text, et al.)

Copyright © 2024 Fran Finnegan & Company LLC – All Rights Reserved.
AboutPrivacyRedactionsHelp — Mon., Apr. 29, 4:34:48.3am ET