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Onto Innovation Inc. – ‘10-Q’ for 7/2/22 – ‘EX-101.LAB’

On:  Tuesday, 8/9/22, at 5:17pm ET   ·   For:  7/2/22   ·   Accession #:  1564590-22-28807   ·   File #:  1-39110

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

 8/09/22  Onto Innovation Inc.              10-Q        7/02/22   84:10M                                    ActiveDisclosure/FA

Quarterly Report   —   Form 10-Q

Filing Table of Contents

Document/Exhibit                   Description                      Pages   Size 

 1: 10-Q        Quarterly Report                                    HTML   2.81M 
 2: EX-31.1     Certification -- §302 - SOA'02                      HTML     41K 
 3: EX-31.2     Certification -- §302 - SOA'02                      HTML     41K 
 4: EX-32.1     Certification -- §906 - SOA'02                      HTML     27K 
 5: EX-32.2     Certification -- §906 - SOA'02                      HTML     27K 
11: R1          Document and Entity Information Document            HTML     76K 
12: R2          Condensed Consolidated Statements of Operations     HTML    107K 
                (Unaudited)                                                      
13: R3          Condensed Consolidated Statements of Comprehensive  HTML     51K 
                Income (Unaudited)                                               
14: R4          Condensed Consolidated Balance Sheets (Unaudited)   HTML    124K 
15: R5          Condensed Consolidated Balance Sheets               HTML     26K 
                (Parenthetical) (Unaudited)                                      
16: R6          Condensed Consolidated Statements of Cash Flows     HTML     93K 
                (Unaudited)                                                      
17: R7          Condensed Consolidated Statements of Stockholders'  HTML     84K 
                Equity (Unaudited)                                               
18: R8          Basis of Presentation                               HTML     31K 
19: R9          Business Combination                                HTML     28K 
20: R10         Fair Value Measurements                             HTML    208K 
21: R11         Marketable Securities                               HTML    251K 
22: R12         Derivative Instruments and Hedging Activities       HTML     38K 
23: R13         Purchased Intangible Assets                         HTML    104K 
24: R14         Balance Sheet Details                               HTML    150K 
25: R15         Commitments and Contingencies                       HTML     61K 
26: R16         Revenue                                             HTML    103K 
27: R17         Share-Based Compensation                            HTML     49K 
28: R18         Other Expense, Net                                  HTML     59K 
29: R19         Income Taxes                                        HTML     63K 
30: R20         Earnings Per Share                                  HTML    105K 
31: R21         Accumulated Other Comprehensive Income (Loss)       HTML     52K 
32: R22         Segment Reporting and Geographic Information        HTML    183K 
33: R23         Share Repurchase Authorization                      HTML     26K 
34: R24         Basis of Presentation (Policies)                    HTML     32K 
35: R25         Fair Value Measurements - (Tables)                  HTML    203K 
36: R26         Marketable Securities - (Tables)                    HTML    252K 
37: R27         Derivative Instruments and Hedging Activities       HTML     36K 
                (Tables)                                                         
38: R28         Purchased Intangible Assets (Tables)                HTML    107K 
39: R29         Balance Sheet Details (Tables)                      HTML    158K 
40: R30         Commitments and Contingencies (Tables)              HTML     50K 
41: R31         Revenue (Tables)                                    HTML    101K 
42: R32         Share-Based Compensation - (Tables)                 HTML     46K 
43: R33         Other Expense, Net (Tables)                         HTML     59K 
44: R34         Income Taxes - (Tables)                             HTML     58K 
45: R35         Earnings Per Share (Tables)                         HTML    103K 
46: R36         Accumulated Other Comprehensive Income (Loss)       HTML     52K 
                (Tables)                                                         
47: R37         Segment Reporting and Geographic Information -      HTML    182K 
                (Tables)                                                         
48: R38         Business Combination - Textual (Details)            HTML     39K 
49: R39         Fair Value Measurements - Assets and Liabilities    HTML     80K 
                Carried at Fair Value Measured on a Recurring                    
                Basis (Details)                                                  
50: R40         Marketable Securities - Schedule of Marketable      HTML     50K 
                Securities by Category (Details)                                 
51: R41         Marketable Securities - Schedule of Amortized Cost  HTML     44K 
                and Estimated Fair Value of Marketable Securities                
                Classified by Maturity Date (Details)                            
52: R42         Marketable Securities - Summary of Estimated Fair   HTML     53K 
                Value and Gross Unrealized Holding Losses of                     
                Marketable Securities in Unrealized Loss Position                
                (Details)                                                        
53: R43         Derivative Instruments and Hedging Activities -     HTML     28K 
                Forward Contracts and Related Fair Values                        
                (Details)                                                        
54: R44         Purchased Intangible Assets - Schedule of           HTML     46K 
                Purchased Intangible Assets (Details)                            
55: R45         Purchased Intangible Assets - Schedule of           HTML     41K 
                Estimated Future Amortization Expenses (Details)                 
56: R46         Balance Sheet Details - Schedule of Inventories     HTML     34K 
                (Details)                                                        
57: R47         Balance Sheet Details - Schedule of Property,       HTML     44K 
                Plant and Equipment, Net (Details)                               
58: R48         Balance Sheet Details - Schedule of Other Assets    HTML     29K 
                (Details)                                                        
59: R49         Balance Sheet Details - Schedule of Accrued         HTML     33K 
                Liabilities (Details)                                            
60: R50         Balance Sheet Details - Schedule of Other Current   HTML     37K 
                Liabilities (Details)                                            
61: R51         Balance Sheet Details - Schedule of Other           HTML     37K 
                Non-Current Liabilities (Details)                                
62: R52         Commitments and Contingencies - Textual (Details)   HTML     40K 
63: R53         Commitments and Contingencies - Schedule of         HTML     32K 
                Changes in Warranty Reserves (Details)                           
64: R54         Revenue - Schedule of Disaggregation of Revenue by  HTML     34K 
                Timing of Revenue (Details)                                      
65: R55         Revenue - Additional Information (Details)          HTML     26K 
66: R56         Revenue - Schedule of Changes in Deferred Revenue   HTML     34K 
                (Details)                                                        
67: R57         Share-Based Compensation - Summary of Restricted    HTML     48K 
                Stock Unit Activity (Details)                                    
68: R58         Share-Based Compensation - Textual (Details)        HTML     41K 
69: R59         Other Expense, Net - Schedule of Other Expense,     HTML     31K 
                Net (Details)                                                    
70: R60         Income Taxes - Details of Income Tax (Details)      HTML     35K 
71: R61         Income Taxes - Textual (Details)                    HTML     25K 
72: R62         Earnings Per Share - Schedule of Basic and Diluted  HTML     59K 
                Earnings Per Share (Details)                                     
73: R63         Accumulated Other Comprehensive Income (Loss) -     HTML     42K 
                Components of Accumulated Other Comprehensive                    
                Loss, Net of Tax (Details)                                       
74: R64         Accumulated Other Comprehensive Income (Loss) -     HTML     27K 
                Additional Information (Details)                                 
75: R65         Segment Reporting and Geographic Information -      HTML     25K 
                Additional Information (Details)                                 
76: R66         Segment Reporting and Geographic Information -      HTML     47K 
                Schedule of Revenue from External Customers by                   
                Products and Services (Details)                                  
77: R67         Segment Reporting and Geographic Information -      HTML     45K 
                Schedule of Revenue from External Customers                      
                Attributed to Foreign Countries by Geographic Area               
                (Details)                                                        
78: R68         Segment Reporting and Geographic Information -      HTML     35K 
                Schedule of Revenue by Major Customer by Reporting               
                Segments (Details)                                               
79: R69         Share Repurchase Authorization - Textual (Details)  HTML     32K 
82: XML         IDEA XML File -- Filing Summary                      XML    156K 
80: XML         XBRL Instance -- onto-10q_20220702_htm               XML   3.16M 
81: EXCEL       IDEA Workbook of Financial Reports                  XLSX    121K 
 7: EX-101.CAL  XBRL Calculations -- onto-20220702_cal               XML    183K 
 8: EX-101.DEF  XBRL Definitions -- onto-20220702_def                XML    309K 
 9: EX-101.LAB  XBRL Labels -- onto-20220702_lab                     XML    945K 
10: EX-101.PRE  XBRL Presentations -- onto-20220702_pre              XML    693K 
 6: EX-101.SCH  XBRL Schema -- onto-20220702                         XSD    152K 
83: JSON        XBRL Instance as JSON Data -- MetaLinks              332±   532K 
84: ZIP         XBRL Zipped Folder -- 0001564590-22-028807-xbrl      Zip    263K

‘EX-101.LAB’   —   XBRL Labels — onto-20220702_lab

This Exhibit is an XBRL XML File.

                                                                                                                                                                                
<?xml version="1.0" standalone="yes" encoding="windows-1252"?>
<!-- DFIN ActiveDisclosure(SM) XBRL Linkbase Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date : 2022-08-08T16:42:56.7141743+00:00 -->
<!-- Version : 5.0.1.747 -->
<!-- Package ID : 4fc44d86180b4cdfb2d650485e0d2cd0 -->
<!-- Copyright (c) 2022 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<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" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
<link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedLabel" xlink:type="simple"/>
<link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedNetLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedNetLabel" xlink:type="simple"/>
<link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedPeriodEndLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedPeriodEndLabel" xlink:type="simple"/>
<link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedPeriodStartLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedPeriodStartLabel" xlink:type="simple"/>
<link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTerseLabel" xlink:type="simple"/>
<link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTotalLabel" xlink:type="simple"/>
<link:roleRef roleURI="http://www.xbrl.org/2009/role/netLabel" xlink:href="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd#netLabel" xlink:type="simple"/>
<link:roleRef roleURI="http://fasb.org/us-gaap/role/label/axisDefault" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-roles-2022.xsd#axisDefault" xlink:type="simple"/>
<link:labelLink xlink:role="http://www.xbrl.org/2003/role/link" xlink:type="extended">
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityCentralIndexKey" xlink:type="locator" xlink:label="dei_EntityCentralIndexKey"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Central Index Key </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityCentralIndexKey" xlink:to="dei_EntityCentralIndexKey_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveYearsAmortizedCost" xlink:type="locator" xlink:label="onto_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveYearsAmortizedCost"/>
<link:label xml:lang="en-US" xlink:label="onto_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveYearsAmortizedCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Available for sale securities debt maturities after five years amortized cost. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveYearsAmortizedCost" xlink:to="onto_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveYearsAmortizedCost_lbl"/>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_CoverAbstract" xlink:type="locator" xlink:label="dei_CoverAbstract"/>
<link:label xml:lang="en-US" xlink:label="dei_CoverAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Cover [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_CoverAbstract" xlink:to="dei_CoverAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityRegistrantName" xlink:type="locator" xlink:label="dei_EntityRegistrantName"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityRegistrantName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Registrant Name </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityRegistrantName" xlink:to="dei_EntityRegistrantName_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityRegistrantName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Registrant Name </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_TradingSymbol" xlink:type="locator" xlink:label="dei_TradingSymbol"/>
<link:label xml:lang="en-US" xlink:label="dei_TradingSymbol_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Trading Symbol </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_TradingSymbol" xlink:to="dei_TradingSymbol_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_TradingSymbol_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Trading Symbol </link:label>
<link:label xml:lang="en-US" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Central Index Key </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_CurrentFiscalYearEndDate" xlink:type="locator" xlink:label="dei_CurrentFiscalYearEndDate"/>
<link:label xml:lang="en-US" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Current Fiscal Year End Date </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_CurrentFiscalYearEndDate" xlink:to="dei_CurrentFiscalYearEndDate_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Current Fiscal Year End Date </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityFilerCategory" xlink:type="locator" xlink:label="dei_EntityFilerCategory"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityFilerCategory_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Filer Category </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityFilerCategory" xlink:to="dei_EntityFilerCategory_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityFilerCategory_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Filer Category </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentType" xlink:type="locator" xlink:label="dei_DocumentType"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentType_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Document Type </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentType" xlink:to="dei_DocumentType_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentType_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Document Type </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentPeriodEndDate" xlink:type="locator" xlink:label="dei_DocumentPeriodEndDate"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Document Period End Date </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentPeriodEndDate" xlink:to="dei_DocumentPeriodEndDate_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Document Period End Date </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentFiscalYearFocus" xlink:type="locator" xlink:label="dei_DocumentFiscalYearFocus"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentFiscalYearFocus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Document Fiscal Year Focus </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentFiscalYearFocus" xlink:to="dei_DocumentFiscalYearFocus_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentFiscalYearFocus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Document Fiscal Year Focus </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentFiscalPeriodFocus" xlink:type="locator" xlink:label="dei_DocumentFiscalPeriodFocus"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Document Fiscal Period Focus </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentFiscalPeriodFocus" xlink:to="dei_DocumentFiscalPeriodFocus_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Document Fiscal Period Focus </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentQuarterlyReport" xlink:type="locator" xlink:label="dei_DocumentQuarterlyReport"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentQuarterlyReport_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Document Quarterly Report </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentQuarterlyReport" xlink:to="dei_DocumentQuarterlyReport_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentQuarterlyReport_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Document Quarterly Report </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentTransitionReport" xlink:type="locator" xlink:label="dei_DocumentTransitionReport"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentTransitionReport_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Document Transition Report </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentTransitionReport" xlink:to="dei_DocumentTransitionReport_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_DocumentTransitionReport_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Document Transition Report </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityInteractiveDataCurrent" xlink:type="locator" xlink:label="dei_EntityInteractiveDataCurrent"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityInteractiveDataCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Interactive Data Current </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityInteractiveDataCurrent" xlink:to="dei_EntityInteractiveDataCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityInteractiveDataCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Interactive Data Current </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_AmendmentFlag" xlink:type="locator" xlink:label="dei_AmendmentFlag"/>
<link:label xml:lang="en-US" xlink:label="dei_AmendmentFlag_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Amendment Flag </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_AmendmentFlag" xlink:to="dei_AmendmentFlag_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_AmendmentFlag_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Amendment Flag </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntitySmallBusiness" xlink:type="locator" xlink:label="dei_EntitySmallBusiness"/>
<link:label xml:lang="en-US" xlink:label="dei_EntitySmallBusiness_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Small Business </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntitySmallBusiness" xlink:to="dei_EntitySmallBusiness_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntitySmallBusiness_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Small Business </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityEmergingGrowthCompany" xlink:type="locator" xlink:label="dei_EntityEmergingGrowthCompany"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityEmergingGrowthCompany_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Emerging Growth Company </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityEmergingGrowthCompany" xlink:to="dei_EntityEmergingGrowthCompany_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityEmergingGrowthCompany_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Emerging Growth Company </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityCurrentReportingStatus" xlink:type="locator" xlink:label="dei_EntityCurrentReportingStatus"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityCurrentReportingStatus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Current Reporting Status </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityCurrentReportingStatus" xlink:to="dei_EntityCurrentReportingStatus_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityCurrentReportingStatus_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Current Reporting Status </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityShellCompany" xlink:type="locator" xlink:label="dei_EntityShellCompany"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityShellCompany_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Shell Company </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityShellCompany" xlink:to="dei_EntityShellCompany_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityShellCompany_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Shell Company </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_Security12bTitle" xlink:type="locator" xlink:label="dei_Security12bTitle"/>
<link:label xml:lang="en-US" xlink:label="dei_Security12bTitle_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Title of 12(b) Security </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_Security12bTitle" xlink:to="dei_Security12bTitle_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_Security12bTitle_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Security12b Title </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_SecurityExchangeName" xlink:type="locator" xlink:label="dei_SecurityExchangeName"/>
<link:label xml:lang="en-US" xlink:label="dei_SecurityExchangeName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Security Exchange Name </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_SecurityExchangeName" xlink:to="dei_SecurityExchangeName_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_SecurityExchangeName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Security Exchange Name </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityCommonStockSharesOutstanding" xlink:type="locator" xlink:label="dei_EntityCommonStockSharesOutstanding"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Common Stock, Shares Outstanding </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityCommonStockSharesOutstanding" xlink:to="dei_EntityCommonStockSharesOutstanding_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Common Stock Shares Outstanding </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityFileNumber" xlink:type="locator" xlink:label="dei_EntityFileNumber"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityFileNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity File Number </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityFileNumber" xlink:to="dei_EntityFileNumber_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityFileNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity File Number </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityIncorporationStateCountryCode" xlink:type="locator" xlink:label="dei_EntityIncorporationStateCountryCode"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityIncorporationStateCountryCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Incorporation, State or Country Code </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityIncorporationStateCountryCode" xlink:to="dei_EntityIncorporationStateCountryCode_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityIncorporationStateCountryCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Incorporation State Country Code </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityTaxIdentificationNumber" xlink:type="locator" xlink:label="dei_EntityTaxIdentificationNumber"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Tax Identification Number </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityTaxIdentificationNumber" xlink:to="dei_EntityTaxIdentificationNumber_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Tax Identification Number </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressAddressLine1" xlink:type="locator" xlink:label="dei_EntityAddressAddressLine1"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Address, Address Line One </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressAddressLine1" xlink:to="dei_EntityAddressAddressLine1_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Address Address Line1 </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressCityOrTown" xlink:type="locator" xlink:label="dei_EntityAddressCityOrTown"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Address, City or Town </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressCityOrTown" xlink:to="dei_EntityAddressCityOrTown_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Address City Or Town </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressStateOrProvince" xlink:type="locator" xlink:label="dei_EntityAddressStateOrProvince"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Address, State or Province </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressStateOrProvince" xlink:to="dei_EntityAddressStateOrProvince_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Address State Or Province </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressPostalZipCode" xlink:type="locator" xlink:label="dei_EntityAddressPostalZipCode"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Entity Address, Postal Zip Code </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressPostalZipCode" xlink:to="dei_EntityAddressPostalZipCode_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Entity Address Postal Zip Code </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_CityAreaCode" xlink:type="locator" xlink:label="dei_CityAreaCode"/>
<link:label xml:lang="en-US" xlink:label="dei_CityAreaCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> City Area Code </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_CityAreaCode" xlink:to="dei_CityAreaCode_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_CityAreaCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> City Area Code </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_LocalPhoneNumber" xlink:type="locator" xlink:label="dei_LocalPhoneNumber"/>
<link:label xml:lang="en-US" xlink:label="dei_LocalPhoneNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Local Phone Number </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_LocalPhoneNumber" xlink:to="dei_LocalPhoneNumber_lbl"/>
<link:label xml:lang="en-US" xlink:label="dei_LocalPhoneNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Local Phone Number </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementAbstract" xlink:type="locator" xlink:label="us-gaap_IncomeStatementAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncomeStatementAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Income Statement [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_IncomeStatementAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:type="locator" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Revenue </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:to="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Revenue From Contract With Customer Excluding Assessed Tax </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostOfRevenue" xlink:type="locator" xlink:label="us-gaap_CostOfRevenue"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CostOfRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Cost of revenue </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CostOfRevenue" xlink:to="us-gaap_CostOfRevenue_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CostOfRevenue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Cost Of Revenue </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GrossProfit" xlink:type="locator" xlink:label="us-gaap_GrossProfit"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_GrossProfit_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Gross profit </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GrossProfit" xlink:to="us-gaap_GrossProfit_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_GrossProfit_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Gross Profit </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingExpensesAbstract" xlink:type="locator" xlink:label="us-gaap_OperatingExpensesAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingExpensesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Operating expenses: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_OperatingExpensesAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingExpensesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Operating Expenses [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:type="locator" xlink:label="us-gaap_ResearchAndDevelopmentExpense"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ResearchAndDevelopmentExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Research and development </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ResearchAndDevelopmentExpense" xlink:to="us-gaap_ResearchAndDevelopmentExpense_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ResearchAndDevelopmentExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Research And Development Expense </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SellingAndMarketingExpense" xlink:type="locator" xlink:label="us-gaap_SellingAndMarketingExpense"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SellingAndMarketingExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Sales and marketing </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SellingAndMarketingExpense" xlink:to="us-gaap_SellingAndMarketingExpense_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SellingAndMarketingExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Selling And Marketing Expense </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:type="locator" xlink:label="us-gaap_GeneralAndAdministrativeExpense"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_GeneralAndAdministrativeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> General and administrative </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeneralAndAdministrativeExpense" xlink:to="us-gaap_GeneralAndAdministrativeExpense_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_GeneralAndAdministrativeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> General And Administrative Expense </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:type="locator" xlink:label="us-gaap_AmortizationOfIntangibleAssets"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Amortization </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AmortizationOfIntangibleAssets" xlink:to="us-gaap_AmortizationOfIntangibleAssets_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Amortization Of Intangible Assets </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingExpenses" xlink:type="locator" xlink:label="us-gaap_OperatingExpenses"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total operating expenses </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_OperatingExpenses_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Operating Expenses </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingIncomeLoss" xlink:type="locator" xlink:label="us-gaap_OperatingIncomeLoss"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingIncomeLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Operating income </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingIncomeLoss" xlink:to="us-gaap_OperatingIncomeLoss_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingIncomeLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Operating Income Loss </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet" xlink:type="locator" xlink:label="us-gaap_InterestIncomeExpenseNonoperatingNet"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InterestIncomeExpenseNonoperatingNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Interest income, net </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestIncomeExpenseNonoperatingNet" xlink:to="us-gaap_InterestIncomeExpenseNonoperatingNet_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InterestIncomeExpenseNonoperatingNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Interest Income Expense Nonoperating Net </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:type="locator" xlink:label="us-gaap_OtherNonoperatingIncomeExpense"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherNonoperatingIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Other expense, net </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherNonoperatingIncomeExpense" xlink:to="us-gaap_OtherNonoperatingIncomeExpense_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherNonoperatingIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Nonoperating Income Expense </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Income before provision for income taxes </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_IncomeTaxExpenseBenefit"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Provision for income taxes </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="us-gaap_IncomeTaxExpenseBenefit_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Income Tax Expense Benefit </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss" xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Net income </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_NetIncomeLoss_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Net Income Loss </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_EarningsPerSharesBasicAndDilutedAbstract" xlink:type="locator" xlink:label="onto_EarningsPerSharesBasicAndDilutedAbstract"/>
<link:label xml:lang="en-US" xlink:label="onto_EarningsPerSharesBasicAndDilutedAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Earnings per share: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_EarningsPerSharesBasicAndDilutedAbstract" xlink:to="onto_EarningsPerSharesBasicAndDilutedAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_EarningsPerSharesBasicAndDilutedAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Earnings Per Shares Basic And Diluted [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareBasic" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareBasic"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Basic </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareBasic" xlink:to="us-gaap_EarningsPerShareBasic_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Earnings Per Share Basic </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareDiluted" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareDiluted"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Diluted </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareDiluted" xlink:to="us-gaap_EarningsPerShareDiluted_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Earnings Per Share Diluted </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Weighted average shares outstanding: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Weighted Average Number Of Shares Outstanding [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Basic </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Weighted Average Number Of Shares Outstanding Basic </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Diluted </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Weighted Average Number Of Diluted Shares Outstanding </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:type="locator" xlink:label="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Statement Of Income And Comprehensive Income [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:to="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Net income </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Other comprehensive loss, net of tax: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:to="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Change in net unrealized gains (losses) on available-for-sale marketable securities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments Net Of Tax </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Change in currency translation adjustments </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total other comprehensive loss, net of tax </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:to="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:type="locator" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total comprehensive income </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_ComprehensiveIncomeNetOfTax_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Comprehensive Income Net Of Tax </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:type="locator" xlink:label="us-gaap_StatementOfFinancialPositionAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StatementOfFinancialPositionAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Statement Of Financial Position [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfFinancialPositionAbstract" xlink:to="us-gaap_StatementOfFinancialPositionAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsAbstract" xlink:type="locator" xlink:label="us-gaap_AssetsAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> ASSETS </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsAbstract" xlink:to="us-gaap_AssetsAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Assets [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsCurrentAbstract" xlink:type="locator" xlink:label="us-gaap_AssetsCurrentAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Current Assets: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsCurrentAbstract" xlink:to="us-gaap_AssetsCurrentAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Assets Current [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Cash and cash equivalents </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Cash And Cash Equivalents At Carrying Value </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Marketable securities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Available For Sale Securities Debt Securities Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:type="locator" xlink:label="us-gaap_AccountsReceivableNetCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accounts receivable, less allowance of $1,439 and $1,303 </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsReceivableNetCurrent" xlink:to="us-gaap_AccountsReceivableNetCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accounts Receivable Net Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InventoryNet" xlink:type="locator" xlink:label="us-gaap_InventoryNet"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InventoryNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Inventories, net </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryNet" xlink:to="us-gaap_InventoryNet_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InventoryNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Inventory Net </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:type="locator" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Prepaid expenses and other current assets </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Prepaid Expense And Other Assets Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsCurrent" xlink:type="locator" xlink:label="us-gaap_AssetsCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AssetsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total current assets </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_AssetsCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AssetsCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Assets Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentNet"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Property, plant and equipment, net </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentNet" xlink:to="us-gaap_PropertyPlantAndEquipmentNet_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Property Plant And Equipment Net </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Goodwill" xlink:type="locator" xlink:label="us-gaap_Goodwill"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_Goodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Goodwill </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Goodwill" xlink:to="us-gaap_Goodwill_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_Goodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Goodwill </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:type="locator" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Identifiable intangible assets, net </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:to="us-gaap_IntangibleAssetsNetExcludingGoodwill_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Intangible Assets Net Excluding Goodwill </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Deferred income taxes </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxAssetsNet" xlink:to="us-gaap_DeferredIncomeTaxAssetsNet_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Deferred Income Tax Assets Net </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsNoncurrent" xlink:type="locator" xlink:label="us-gaap_OtherAssetsNoncurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Other assets </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherAssetsNoncurrent" xlink:to="us-gaap_OtherAssetsNoncurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Assets Noncurrent </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Assets" xlink:type="locator" xlink:label="us-gaap_Assets"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_Assets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total assets </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Assets" xlink:to="us-gaap_Assets_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_Assets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Assets </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:type="locator" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> LIABILITIES AND STOCKHOLDERS’ EQUITY </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Liabilities And Stockholders Equity [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:type="locator" xlink:label="us-gaap_LiabilitiesCurrentAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Current liabilities: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesCurrentAbstract" xlink:to="us-gaap_LiabilitiesCurrentAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Liabilities Current [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsPayableCurrent" xlink:type="locator" xlink:label="us-gaap_AccountsPayableCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccountsPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accounts payable </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsPayableCurrent" xlink:to="us-gaap_AccountsPayableCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccountsPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accounts Payable Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_AccruedLiabilitiesCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccruedLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accrued liabilities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccruedLiabilitiesCurrent" xlink:to="us-gaap_AccruedLiabilitiesCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccruedLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accrued Liabilities Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Deferred revenue </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiabilityCurrent" xlink:to="us-gaap_ContractWithCustomerLiabilityCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Contract With Customer Liability Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_OtherLiabilitiesCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Other current liabilities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherLiabilitiesCurrent" xlink:to="us-gaap_OtherLiabilitiesCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Liabilities Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_LiabilitiesCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total current liabilities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_LiabilitiesCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Liabilities Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DeferredIncomeTaxLiabilitiesNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Deferred income taxes </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:to="us-gaap_DeferredIncomeTaxLiabilitiesNet_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DeferredIncomeTaxLiabilitiesNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Deferred Income Tax Liabilities Net </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:type="locator" xlink:label="us-gaap_OtherLiabilitiesNoncurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Other non-current liabilities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherLiabilitiesNoncurrent" xlink:to="us-gaap_OtherLiabilitiesNoncurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Liabilities Noncurrent </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Liabilities" xlink:type="locator" xlink:label="us-gaap_Liabilities"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_Liabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total liabilities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_Liabilities_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_Liabilities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Liabilities </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommitmentsAndContingencies" xlink:type="locator" xlink:label="us-gaap_CommitmentsAndContingencies"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommitmentsAndContingencies_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Commitments and contingencies </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommitmentsAndContingencies" xlink:to="us-gaap_CommitmentsAndContingencies_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommitmentsAndContingencies_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Commitments And Contingencies </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquityAbstract" xlink:type="locator" xlink:label="us-gaap_StockholdersEquityAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Stockholders’ equity: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_StockholdersEquityAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Stockholders Equity [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockValue" xlink:type="locator" xlink:label="us-gaap_CommonStockValue"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Common stock </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockValue" xlink:to="us-gaap_CommonStockValue_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Common Stock Value </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:type="locator" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Additional paid-in capital </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdditionalPaidInCapitalCommonStock" xlink:to="us-gaap_AdditionalPaidInCapitalCommonStock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Additional Paid In Capital Common Stock </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accumulated other comprehensive (loss) income </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accumulated Other Comprehensive Income Loss Net Of Tax </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:type="locator" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Retained earnings </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetainedEarningsAccumulatedDeficit" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Retained Earnings Accumulated Deficit </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity" xlink:type="locator" xlink:label="us-gaap_StockholdersEquity"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total stockholders’ equity </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_StockholdersEquity_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Stockholders Equity </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:type="locator" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total liabilities and stockholders’ equity </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_LiabilitiesAndStockholdersEquity_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Liabilities And Stockholders Equity </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:type="locator" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Allowances for doubtful accounts </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:to="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Allowance For Doubtful Accounts Receivable Current </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_AcquiredInventoryStepUpAmortization" xlink:type="locator" xlink:label="onto_AcquiredInventoryStepUpAmortization"/>
<link:label xml:lang="en-US" xlink:label="onto_AcquiredInventoryStepUpAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Acquired inventory step up amortization. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_AcquiredInventoryStepUpAmortization" xlink:to="onto_AcquiredInventoryStepUpAmortization_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_ProvisionForInventoryValuation" xlink:type="locator" xlink:label="onto_ProvisionForInventoryValuation"/>
<link:label xml:lang="en-US" xlink:label="onto_ProvisionForInventoryValuation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Provision for inventory valuation. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_ProvisionForInventoryValuation" xlink:to="onto_ProvisionForInventoryValuation_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:type="locator" xlink:label="us-gaap_StatementOfCashFlowsAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StatementOfCashFlowsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Statement Of Cash Flows [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_StatementOfCashFlowsAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Cash flows from operating activities: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Net Cash Provided By Used In Operating Activities [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProfitLoss" xlink:type="locator" xlink:label="us-gaap_ProfitLoss"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProfitLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Net income </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProfitLoss" xlink:to="us-gaap_ProfitLoss_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProfitLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Profit Loss </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="locator" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Adjustments to reconcile net income to net cash and cash equivalents provided by operating activities: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Amortization of intangibles </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Depreciation" xlink:type="locator" xlink:label="us-gaap_Depreciation"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_Depreciation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Depreciation </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Depreciation" xlink:to="us-gaap_Depreciation_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_Depreciation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Depreciation </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensation" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensation"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Share-based compensation </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensation" xlink:to="us-gaap_ShareBasedCompensation_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation </link:label>
<link:label xml:lang="en-US" xlink:label="onto_AcquiredInventoryStepUpAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Acquired inventory step-up amortization </link:label>
<link:label xml:lang="en-US" xlink:label="onto_AcquiredInventoryStepUpAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Acquired Inventory Step Up Amortization </link:label>
<link:label xml:lang="en-US" xlink:label="onto_ProvisionForInventoryValuation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Provision for inventory valuation </link:label>
<link:label xml:lang="en-US" xlink:label="onto_ProvisionForInventoryValuation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Provision For Inventory Valuation </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredIncomeTaxesAndTaxCredits" xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxesAndTaxCredits"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DeferredIncomeTaxesAndTaxCredits_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Deferred income taxes </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxesAndTaxCredits" xlink:to="us-gaap_DeferredIncomeTaxesAndTaxCredits_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DeferredIncomeTaxesAndTaxCredits_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Deferred Income Taxes And Tax Credits </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:type="locator" xlink:label="us-gaap_OtherNoncashIncomeExpense"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherNoncashIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Other, net </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherNoncashIncomeExpense" xlink:to="us-gaap_OtherNoncashIncomeExpense_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherNoncashIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Noncash Income Expense </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Changes in operating assets and liabilities, net of effects of business acquired </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Increase Decrease In Other Operating Capital Net </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Net cash and cash equivalents provided by operating activities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Net Cash Provided By Used In Operating Activities </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Cash flows from investing activities: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Net Cash Provided By Used In Investing Activities [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireMarketableSecurities" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireMarketableSecurities"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireMarketableSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Purchases of marketable securities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireMarketableSecurities" xlink:to="us-gaap_PaymentsToAcquireMarketableSecurities_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireMarketableSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Payments To Acquire Marketable Securities </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities" xlink:type="locator" xlink:label="us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Proceeds from maturities and sales of marketable securities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities" xlink:to="us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Proceeds From Sale And Maturity Of Marketable Securities </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Purchase of business, net of cash acquired </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:to="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Payments To Acquire Businesses Net Of Cash Acquired </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Purchases of property, plant and equipment </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Payments To Acquire Property Plant And Equipment </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Net cash and cash equivalents used in investing activities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Net Cash Provided By Used In Investing Activities </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Cash flows from financing activities: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Net Cash Provided By Used In Financing Activities [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:type="locator" xlink:label="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Tax payments related to shares withheld for share-based compensation plans </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:to="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Payments Related To Tax Withholding For Share Based Compensation </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities" xlink:type="locator" xlink:label="us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Payment of contingent consideration for acquired business </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities" xlink:to="us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Payment For Contingent Consideration Liability Financing Activities </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Issuance of shares through share-based compensation plans </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:to="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Net cash and cash equivalents used in financing activities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Net Cash Provided By Used In Financing Activities </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:type="locator" xlink:label="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Effect of exchange rate changes on cash and cash equivalents </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:to="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:type="locator" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Net increase (decrease) in cash and cash equivalents </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:type="locator" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel"> Cash and cash equivalents at beginning of period </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:to="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel"> Cash and cash equivalents at end of period </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:type="locator" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Supplemental disclosure of cash flow information: </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="us-gaap_SupplementalCashFlowInformationAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Supplemental Cash Flow Information [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxesPaidNet" xlink:type="locator" xlink:label="us-gaap_IncomeTaxesPaidNet"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Income taxes paid (net of refunds) </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxesPaidNet" xlink:to="us-gaap_IncomeTaxesPaidNet_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Income Taxes Paid Net </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_AdjustmentsToAdditionalPaidInCapitalIncomeTaxDeficiencyFromShareBasedCompensations" xlink:type="locator" xlink:label="onto_AdjustmentsToAdditionalPaidInCapitalIncomeTaxDeficiencyFromShareBasedCompensations"/>
<link:label xml:lang="en-US" xlink:label="onto_AdjustmentsToAdditionalPaidInCapitalIncomeTaxDeficiencyFromShareBasedCompensations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Adjustments to additional paid in capital income tax deficiency from share based compensations. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_AdjustmentsToAdditionalPaidInCapitalIncomeTaxDeficiencyFromShareBasedCompensations" xlink:to="onto_AdjustmentsToAdditionalPaidInCapitalIncomeTaxDeficiencyFromShareBasedCompensations_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementOfStockholdersEquityAbstract" xlink:type="locator" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Statement Of Stockholders Equity [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfStockholdersEquityAbstract" xlink:to="us-gaap_StatementOfStockholdersEquityAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StatementTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Statement [Table] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StatementTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Statement [Table] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Retained Earnings (Accumulated Deficit) [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_StatementEquityComponentsAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Statement Equity Components [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain" xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EquityComponentDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Equity Component </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_EquityComponentDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EquityComponentDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Equity Component [Domain] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember" xlink:type="locator" xlink:label="us-gaap_CommonStockMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Common Stock [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockMember" xlink:to="us-gaap_CommonStockMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Common Stock [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:type="locator" xlink:label="us-gaap_AdditionalPaidInCapitalMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Additional Paid-in Capital [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdditionalPaidInCapitalMember" xlink:to="us-gaap_AdditionalPaidInCapitalMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Additional Paid In Capital [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accumulated Other Comprehensive Income (Loss) [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accumulated Other Comprehensive Income [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsMember" xlink:type="locator" xlink:label="us-gaap_RetainedEarningsMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Retained Earnings [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetainedEarningsMember" xlink:to="us-gaap_RetainedEarningsMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Retained Earnings [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StatementLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Statement [Line Items] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementLineItems_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StatementLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Statement [Line Items] </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel"> Balance </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesIssued" xlink:type="locator" xlink:label="us-gaap_CommonStockSharesIssued"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel"> Balance, Shares </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockSharesIssued" xlink:to="us-gaap_CommonStockSharesIssued_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Common Stock Shares Issued </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Net income </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:type="locator" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Share-based compensation </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Issuance of shares through share-based compensation plans </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:to="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Stock Issued During Period Value Share Based Compensation </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Issuance of shares through share-based compensation plans, Shares </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:to="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Stock Issued During Period Shares Share Based Compensation </link:label>
<link:label xml:lang="en-US" xlink:label="onto_AdjustmentsToAdditionalPaidInCapitalIncomeTaxDeficiencyFromShareBasedCompensations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Share-based compensation plan withholdings </link:label>
<link:label xml:lang="en-US" xlink:label="onto_AdjustmentsToAdditionalPaidInCapitalIncomeTaxDeficiencyFromShareBasedCompensations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Adjustments To Additional Paid In Capital Income Tax Deficiency From Share Based Compensations </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation" xlink:type="locator" xlink:label="us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Share-based compensation plan withholdings, Shares </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation" xlink:to="us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Shares Paid For Tax Withholding For Share Based Compensation </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Currency translation </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Unrealized gain (loss) on investments </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel"> Balance </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel"> Balance, shares </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:type="locator" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Organization Consolidation And Presentation Of Financial Statements [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:to="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Basis of Presentation </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:to="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Organization Consolidation And Presentation Of Financial Statements Disclosure [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationsAbstract" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationsAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_BusinessCombinationsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Business Combinations [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessCombinationsAbstract" xlink:to="us-gaap_BusinessCombinationsAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationDisclosureTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_BusinessCombinationDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Business Combination </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessCombinationDisclosureTextBlock" xlink:to="us-gaap_BusinessCombinationDisclosureTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_BusinessCombinationDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Business Combination Disclosure [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueDisclosuresAbstract" xlink:type="locator" xlink:label="us-gaap_FairValueDisclosuresAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueDisclosuresAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Disclosures [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueDisclosuresAbstract" xlink:to="us-gaap_FairValueDisclosuresAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueDisclosuresTextBlock" xlink:type="locator" xlink:label="us-gaap_FairValueDisclosuresTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueDisclosuresTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Fair Value Measurements </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueDisclosuresTextBlock" xlink:to="us-gaap_FairValueDisclosuresTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueDisclosuresTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Disclosures [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MarketableSecuritiesAbstract" xlink:type="locator" xlink:label="us-gaap_MarketableSecuritiesAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_MarketableSecuritiesAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Marketable Securities [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MarketableSecuritiesAbstract" xlink:to="us-gaap_MarketableSecuritiesAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Marketable Securities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock" xlink:to="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Investments In Debt And Marketable Equity Securities And Certain Trading Assets Disclosure [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Derivative Instruments And Hedging Activities Disclosure [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:to="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Derivative Instruments and Hedging Activities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock" xlink:to="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Derivative Instruments And Hedging Activities Disclosure [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:type="locator" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Goodwill And Intangible Assets Disclosure [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract" xlink:to="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IntangibleAssetsDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_IntangibleAssetsDisclosureTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IntangibleAssetsDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Purchased Intangible Assets </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IntangibleAssetsDisclosureTextBlock" xlink:to="us-gaap_IntangibleAssetsDisclosureTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IntangibleAssetsDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Intangible Assets Disclosure [Text Block] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_BalanceSheetDetailsTextBlock" xlink:type="locator" xlink:label="onto_BalanceSheetDetailsTextBlock"/>
<link:label xml:lang="en-US" xlink:label="onto_BalanceSheetDetailsTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Balance sheet details. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_BalanceSheetDetailsTextBlock" xlink:to="onto_BalanceSheetDetailsTextBlock_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_BalanceSheetDetailAbstract" xlink:type="locator" xlink:label="onto_BalanceSheetDetailAbstract"/>
<link:label xml:lang="en-US" xlink:label="onto_BalanceSheetDetailAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Balance Sheet Detail [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_BalanceSheetDetailAbstract" xlink:to="onto_BalanceSheetDetailAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_BalanceSheetDetailAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Balance Sheet Detail [Abstract] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_BalanceSheetDetailsTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Balance Sheet Details </link:label>
<link:label xml:lang="en-US" xlink:label="onto_BalanceSheetDetailsTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Balance Sheet Details [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:type="locator" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Commitments And Contingencies Disclosure [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:to="us-gaap_CommitmentsAndContingenciesDisclosureAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Commitments and Contingencies </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:to="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Commitments And Contingencies Disclosure [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerAbstract" xlink:type="locator" xlink:label="us-gaap_RevenueFromContractWithCustomerAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_RevenueFromContractWithCustomerAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Revenue From Contract With Customer [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueFromContractWithCustomerAbstract" xlink:to="us-gaap_RevenueFromContractWithCustomerAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:type="locator" xlink:label="us-gaap_RevenueFromContractWithCustomerTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_RevenueFromContractWithCustomerTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Revenue </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueFromContractWithCustomerTextBlock" xlink:to="us-gaap_RevenueFromContractWithCustomerTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_RevenueFromContractWithCustomerTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Revenue From Contract With Customer [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:type="locator" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:type="locator" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Share-Based Compensation </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:to="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Disclosure Of Compensation Related Costs Share Based Payments [Text Block] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_OtherIncomeExpenseAbstract" xlink:type="locator" xlink:label="onto_OtherIncomeExpenseAbstract"/>
<link:label xml:lang="en-US" xlink:label="onto_OtherIncomeExpenseAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Other Income (Expense) [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_OtherIncomeExpenseAbstract" xlink:to="onto_OtherIncomeExpenseAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_OtherIncomeExpenseAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Income Expense [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherIncomeAndOtherExpenseDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_OtherIncomeAndOtherExpenseDisclosureTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherIncomeAndOtherExpenseDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Other Expense, Net </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherIncomeAndOtherExpenseDisclosureTextBlock" xlink:to="us-gaap_OtherIncomeAndOtherExpenseDisclosureTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherIncomeAndOtherExpenseDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Income And Other Expense Disclosure [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:type="locator" xlink:label="us-gaap_IncomeTaxDisclosureAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Income Tax Disclosure [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_IncomeTaxDisclosureAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Income Taxes </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxDisclosureTextBlock" xlink:to="us-gaap_IncomeTaxDisclosureTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Income Tax Disclosure [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareAbstract" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Earnings Per Share [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareAbstract" xlink:to="us-gaap_EarningsPerShareAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareTextBlock" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Earnings Per Share </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareTextBlock" xlink:to="us-gaap_EarningsPerShareTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Earnings Per Share [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTaxAbstract" xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTaxAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTaxAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTaxAbstract" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTaxAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComprehensiveIncomeNoteTextBlock" xlink:type="locator" xlink:label="us-gaap_ComprehensiveIncomeNoteTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ComprehensiveIncomeNoteTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accumulated Other Comprehensive Income (Loss) </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ComprehensiveIncomeNoteTextBlock" xlink:to="us-gaap_ComprehensiveIncomeNoteTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ComprehensiveIncomeNoteTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Comprehensive Income Note [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingAbstract" xlink:type="locator" xlink:label="us-gaap_SegmentReportingAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Segment Reporting [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingAbstract" xlink:to="us-gaap_SegmentReportingAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingDisclosureTextBlock" xlink:type="locator" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Segment Reporting and Geographic Information </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingDisclosureTextBlock" xlink:to="us-gaap_SegmentReportingDisclosureTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Segment Reporting Disclosure [Text Block] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_ShareRepurchaseTextBlock" xlink:type="locator" xlink:label="onto_ShareRepurchaseTextBlock"/>
<link:label xml:lang="en-US" xlink:label="onto_ShareRepurchaseTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Share Repurchase [Text Block] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_ShareRepurchaseTextBlock" xlink:to="onto_ShareRepurchaseTextBlock_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_ShareRepurchaseProgramAbstract" xlink:type="locator" xlink:label="onto_ShareRepurchaseProgramAbstract"/>
<link:label xml:lang="en-US" xlink:label="onto_ShareRepurchaseProgramAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Share Repurchase Program [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_ShareRepurchaseProgramAbstract" xlink:to="onto_ShareRepurchaseProgramAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_ShareRepurchaseProgramAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Repurchase Program [Abstract] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_ShareRepurchaseTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Share Repurchase Authorization </link:label>
<link:label xml:lang="en-US" xlink:label="onto_ShareRepurchaseTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Repurchase [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UseOfEstimates" xlink:type="locator" xlink:label="us-gaap_UseOfEstimates"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_UseOfEstimates_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Use of Estimates </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UseOfEstimates" xlink:to="us-gaap_UseOfEstimates_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_UseOfEstimates_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Use Of Estimates </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:type="locator" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Adoption of Accounting Standards </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:to="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> New Accounting Pronouncements Policy Policy [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" xlink:to="us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Marketable Securities by Category </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Debt Securities Available For Sale Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock" xlink:type="locator" xlink:label="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Amortized Cost and Estimated Fair Value of Marketable Securities Classified by Maturity Date </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock" xlink:to="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Investments Classified By Contractual Maturity Date Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Summary of Estimated Fair Value and Gross Unrealized Holding Losses of Marketable Securities in Unrealized Loss Position </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock" xlink:to="us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Unrealized Loss On Investments Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Forward Contracts and Related Fair Values </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock" xlink:to="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Derivative Instruments In Statement Of Financial Position Fair Value [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Purchased Intangible Assets </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock" xlink:to="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Finite Lived Intangible Assets Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Estimated Future Amortization Expenses </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock" xlink:to="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Scheduleof Finite Lived Intangible Assets Future Amortization Expense Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfInventoryCurrentTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfInventoryCurrentTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfInventoryCurrentTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Inventories </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfInventoryCurrentTableTextBlock" xlink:to="us-gaap_ScheduleOfInventoryCurrentTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfInventoryCurrentTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Inventory Current Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Property, Plant and Equipment, Net </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Property Plant And Equipment [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfOtherAssetsTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfOtherAssetsTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfOtherAssetsTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Other Assets </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfOtherAssetsTableTextBlock" xlink:to="us-gaap_ScheduleOfOtherAssetsTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfOtherAssetsTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Other Assets Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Accrued Liabilities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock" xlink:to="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Accrued Liabilities Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherCurrentLiabilitiesTableTextBlock" xlink:type="locator" xlink:label="us-gaap_OtherCurrentLiabilitiesTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherCurrentLiabilitiesTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Other Current Liabilities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherCurrentLiabilitiesTableTextBlock" xlink:to="us-gaap_OtherCurrentLiabilitiesTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherCurrentLiabilitiesTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Current Liabilities Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherNoncurrentLiabilitiesTableTextBlock" xlink:type="locator" xlink:label="us-gaap_OtherNoncurrentLiabilitiesTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherNoncurrentLiabilitiesTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Other Non-Current Liabilities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherNoncurrentLiabilitiesTableTextBlock" xlink:to="us-gaap_OtherNoncurrentLiabilitiesTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherNoncurrentLiabilitiesTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Noncurrent Liabilities Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfProductWarrantyLiabilityTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfProductWarrantyLiabilityTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfProductWarrantyLiabilityTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Changes in Warranty Reserves </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfProductWarrantyLiabilityTableTextBlock" xlink:to="us-gaap_ScheduleOfProductWarrantyLiabilityTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfProductWarrantyLiabilityTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Product Warranty Liability Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueTableTextBlock" xlink:type="locator" xlink:label="us-gaap_DisaggregationOfRevenueTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DisaggregationOfRevenueTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Disaggregation of Revenue </link:label>
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<link:label xml:lang="en-US" xlink:label="us-gaap_DisaggregationOfRevenueTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Disaggregation Of Revenue Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Changes in Deferred Revenue </link:label>
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<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Contract With Customer Asset And Liability Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Summary of Restricted Stock Unit Activity </link:label>
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<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Share Based Compensation Restricted Stock Units Award Activity Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Other Expense, Net </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock" xlink:to="us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Other Nonoperating Income Expense Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Details of Income Tax </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:to="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Components Of Income Tax Expense Benefit Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Basic and Diluted Earnings Per Share </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:to="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Components of Accumulated Other Comprehensive Loss, Net of Tax </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:to="us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Accumulated Other Comprehensive Income Loss Table [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Revenue from External Customers by Products and Services </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock" xlink:to="us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Entity Wide Information Revenue From External Customers By Products And Services [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfRevenueFromExternalCustomersAttributedToForeignCountriesByGeographicAreaTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfRevenueFromExternalCustomersAttributedToForeignCountriesByGeographicAreaTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfRevenueFromExternalCustomersAttributedToForeignCountriesByGeographicAreaTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfRevenueFromExternalCustomersAttributedToForeignCountriesByGeographicAreaTextBlock" xlink:to="us-gaap_ScheduleOfRevenueFromExternalCustomersAttributedToForeignCountriesByGeographicAreaTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfRevenueFromExternalCustomersAttributedToForeignCountriesByGeographicAreaTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Revenue From External Customers Attributed To Foreign Countries By Geographic Area [Text Block] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock" xlink:type="locator" xlink:label="us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule of Revenue by Major Customer by Reporting Segments </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock" xlink:to="us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfRevenueByMajorCustomersByReportingSegmentsTableTextBlock_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Revenue By Major Customers By Reporting Segments Table [Text Block] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_BusinessCombinationPotentialEarnoutAdditionalPayment" xlink:type="locator" xlink:label="onto_BusinessCombinationPotentialEarnoutAdditionalPayment"/>
<link:label xml:lang="en-US" xlink:label="onto_BusinessCombinationPotentialEarnoutAdditionalPayment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Business combination potential earnout additional payment. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_BusinessCombinationPotentialEarnoutAdditionalPayment" xlink:to="onto_BusinessCombinationPotentialEarnoutAdditionalPayment_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_BusinessCombinationPotentialEarnoutSubjectToPrincipalRemainingPeriod" xlink:type="locator" xlink:label="onto_BusinessCombinationPotentialEarnoutSubjectToPrincipalRemainingPeriod"/>
<link:label xml:lang="en-US" xlink:label="onto_BusinessCombinationPotentialEarnoutSubjectToPrincipalRemainingPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Business combination potential earnout subject to principal remaining period. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_BusinessCombinationPotentialEarnoutSubjectToPrincipalRemainingPeriod" xlink:to="onto_BusinessCombinationPotentialEarnoutSubjectToPrincipalRemainingPeriod_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_BusinessCombinationPotentialEarnoutAccrued" xlink:type="locator" xlink:label="onto_BusinessCombinationPotentialEarnoutAccrued"/>
<link:label xml:lang="en-US" xlink:label="onto_BusinessCombinationPotentialEarnoutAccrued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Business combination potential earnout accrued. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_BusinessCombinationPotentialEarnoutAccrued" xlink:to="onto_BusinessCombinationPotentialEarnoutAccrued_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_BusinessAcquisitionAchievedEarnoutPayment" xlink:type="locator" xlink:label="onto_BusinessAcquisitionAchievedEarnoutPayment"/>
<link:label xml:lang="en-US" xlink:label="onto_BusinessAcquisitionAchievedEarnoutPayment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Business acquisition, achieved earnout payment. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_BusinessAcquisitionAchievedEarnoutPayment" xlink:to="onto_BusinessAcquisitionAchievedEarnoutPayment_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule Of Business Acquisitions By Acquisition [Table] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Business Acquisitions By Acquisition [Table] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Business Acquisition </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Business Acquisition [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Business Acquisition, Acquiree </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Business Acquisition Acquiree [Domain] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_InspectrologyLLCMember" xlink:type="locator" xlink:label="onto_InspectrologyLLCMember"/>
<link:label xml:lang="en-US" xlink:label="onto_InspectrologyLLCMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Inspectrology, LLC. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_InspectrologyLLCMember" xlink:to="onto_InspectrologyLLCMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_InspectrologyLLCMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Inspectrology, LLC [Member] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_InspectrologyLLCMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Inspectrology L L C [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis"/>
<link:label xml:lang="en-US" xlink:label="srt_RangeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Statistical Measurement </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeAxis" xlink:to="srt_RangeAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="srt_RangeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Range [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember"/>
<link:label xml:lang="en-US" xlink:label="srt_RangeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Statistical Measurement </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeMember" xlink:to="srt_RangeMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="srt_RangeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Range [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember"/>
<link:label xml:lang="en-US" xlink:label="srt_MaximumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Maximum [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MaximumMember" xlink:to="srt_MaximumMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="srt_MaximumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Maximum [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember"/>
<link:label xml:lang="en-US" xlink:label="srt_MinimumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Minimum [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MinimumMember" xlink:to="srt_MinimumMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="srt_MinimumMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Minimum [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionLineItems"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Business Acquisition [Line Items] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessAcquisitionLineItems_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_BusinessAcquisitionLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Business Acquisition [Line Items] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Business acquisition, cash consideration </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireBusinessesGross" xlink:to="us-gaap_PaymentsToAcquireBusinessesGross_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Payments To Acquire Businesses Gross </link:label>
<link:label xml:lang="en-US" xlink:label="onto_BusinessAcquisitionAchievedEarnoutPayment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Business acquisition, achieved earnout payment </link:label>
<link:label xml:lang="en-US" xlink:label="onto_BusinessAcquisitionAchievedEarnoutPayment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Business Acquisition Achieved Earnout Payment </link:label>
<link:label xml:lang="en-US" xlink:label="onto_BusinessCombinationPotentialEarnoutAdditionalPayment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Business combination potential earnout additional payment </link:label>
<link:label xml:lang="en-US" xlink:label="onto_BusinessCombinationPotentialEarnoutAdditionalPayment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Business Combination Potential Earnout Additional Payment </link:label>
<link:label xml:lang="en-US" xlink:label="onto_BusinessCombinationPotentialEarnoutAccrued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Business combination potential earnout accrued </link:label>
<link:label xml:lang="en-US" xlink:label="onto_BusinessCombinationPotentialEarnoutAccrued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Business Combination Potential Earnout Accrued </link:label>
<link:label xml:lang="en-US" xlink:label="onto_BusinessCombinationPotentialEarnoutSubjectToPrincipalRemainingPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Business combination potential earnout subject to principal remaining period </link:label>
<link:label xml:lang="en-US" xlink:label="onto_BusinessCombinationPotentialEarnoutSubjectToPrincipalRemainingPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Business Combination Potential Earnout Subject To Principal Remaining Period </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:type="locator" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Fair Value Hierarchy and NAV </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value By Fair Value Hierarchy Level [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Fair Value Hierarchy and NAV </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Measurements Fair Value Hierarchy [Domain] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel1Member" xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel1Member"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueInputsLevel1Member" xlink:to="us-gaap_FairValueInputsLevel1Member_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Inputs Level1 [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel2Member" xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel2Member"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Significant Other Observable Inputs (Level 2) [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueInputsLevel2Member" xlink:to="us-gaap_FairValueInputsLevel2Member_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Inputs Level2 [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel3Member" xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel3Member"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Significant Unobservable Inputs (Level 3) [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueInputsLevel3Member" xlink:to="us-gaap_FairValueInputsLevel3Member_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Inputs Level3 [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByMeasurementBasisAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueByMeasurementBasisAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Measurement Basis </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueByMeasurementBasisAxis" xlink:to="us-gaap_FairValueByMeasurementBasisAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueByMeasurementBasisAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value By Measurement Basis [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:type="locator" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Fair Value Disclosure Item Amounts [Default] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:to="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Portion At Fair Value Fair Value Disclosure [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:type="locator" xlink:label="us-gaap_FairValueDisclosureItemAmountsDomain"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueDisclosureItemAmountsDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Fair Value Measurement </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueDisclosureItemAmountsDomain" xlink:to="us-gaap_FairValueDisclosureItemAmountsDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueDisclosureItemAmountsDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Disclosure Item Amounts [Domain] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:type="locator" xlink:label="us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CarryingReportedAmountFairValueDisclosureMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Carrying Value [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:to="us-gaap_CarryingReportedAmountFairValueDisclosureMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CarryingReportedAmountFairValueDisclosureMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Carrying Reported Amount Fair Value Disclosure [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Measurement Frequency </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="us-gaap_FairValueByMeasurementFrequencyAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value By Measurement Frequency [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Measurement Frequency </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementFrequencyDomain" xlink:to="us-gaap_FairValueMeasurementFrequencyDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Measurement Frequency [Domain] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsRecurringMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Fair Value, Measurements, Recurring [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementsRecurringMember" xlink:to="us-gaap_FairValueMeasurementsRecurringMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Measurements Recurring [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByAssetClassAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByAssetClassAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueByAssetClassAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Asset Class </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueByAssetClassAxis" xlink:to="us-gaap_FairValueByAssetClassAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueByAssetClassAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value By Asset Class [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:type="locator" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Asset Class </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation By Asset Class [Domain] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember" xlink:type="locator" xlink:label="us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_USStatesAndPoliticalSubdivisionsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Municipal notes and bonds [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_USStatesAndPoliticalSubdivisionsMember" xlink:to="us-gaap_USStatesAndPoliticalSubdivisionsMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_USStatesAndPoliticalSubdivisionsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> U S States And Political Subdivisions [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesMember" xlink:type="locator" xlink:label="us-gaap_AssetBackedSecuritiesMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AssetBackedSecuritiesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Asset-backed securities [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetBackedSecuritiesMember" xlink:to="us-gaap_AssetBackedSecuritiesMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AssetBackedSecuritiesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Asset Backed Securities [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CertificatesOfDepositMember" xlink:type="locator" xlink:label="us-gaap_CertificatesOfDepositMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CertificatesOfDepositMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Certificates of deposits [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CertificatesOfDepositMember" xlink:to="us-gaap_CertificatesOfDepositMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CertificatesOfDepositMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Certificates Of Deposit [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember" xlink:type="locator" xlink:label="us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Commercial paper [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember" xlink:to="us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Commercial Paper Not Included With Cash And Cash Equivalents [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:type="locator" xlink:label="us-gaap_CorporateDebtSecuritiesMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CorporateDebtSecuritiesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Corporate bonds [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CorporateDebtSecuritiesMember" xlink:to="us-gaap_CorporateDebtSecuritiesMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CorporateDebtSecuritiesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Corporate Debt Securities [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:type="locator" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Available-for-sale debt securities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Available For Sale Securities Debt Securities </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsFairValueDisclosure" xlink:type="locator" xlink:label="us-gaap_AssetsFairValueDisclosure"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AssetsFairValueDisclosure_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total assets </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsFairValueDisclosure" xlink:to="us-gaap_AssetsFairValueDisclosure_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AssetsFairValueDisclosure_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Assets Fair Value Disclosure </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure" xlink:type="locator" xlink:label="us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Foreign currency forward contracts </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure" xlink:to="us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Foreign Currency Contracts Liability Fair Value Disclosure </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationContingentConsiderationLiability"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_BusinessCombinationContingentConsiderationLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Contingent consideration - acquisitions </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessCombinationContingentConsiderationLiability" xlink:to="us-gaap_BusinessCombinationContingentConsiderationLiability_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_BusinessCombinationContingentConsiderationLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Business Combination Contingent Consideration Liability </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:type="locator" xlink:label="us-gaap_LiabilitiesFairValueDisclosure"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesFairValueDisclosure_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total liabilities </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesFairValueDisclosure" xlink:to="us-gaap_LiabilitiesFairValueDisclosure_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LiabilitiesFairValueDisclosure_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Liabilities Fair Value Disclosure </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule Of Available For Sale Securities [Table] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:to="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Available For Sale Securities [Table] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeAxis" xlink:type="locator" xlink:label="us-gaap_InvestmentTypeAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InvestmentTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Investment Type </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentTypeAxis" xlink:to="us-gaap_InvestmentTypeAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InvestmentTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Investment Type [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:type="locator" xlink:label="us-gaap_InvestmentTypeCategorizationMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InvestmentTypeCategorizationMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Investments </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentTypeCategorizationMember" xlink:to="us-gaap_InvestmentTypeCategorizationMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InvestmentTypeCategorizationMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Investment Type Categorization [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USTreasuryAndGovernmentMember" xlink:type="locator" xlink:label="us-gaap_USTreasuryAndGovernmentMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_USTreasuryAndGovernmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Municipal notes and bonds [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_USTreasuryAndGovernmentMember" xlink:to="us-gaap_USTreasuryAndGovernmentMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_USTreasuryAndGovernmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> U S Treasury And Government [Member] </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_CorporateDebtSecuritiesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Corporate bonds [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
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<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_lbl"/>
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<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Fair Value </link:label>
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<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Amortized Cost, Due within one year </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Available For Sale Securities Debt Maturities Within One Year Amortized Cost </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Amortized Cost, Due after one through five years </link:label>
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<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost </link:label>
<link:label xml:lang="en-US" xlink:label="onto_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveYearsAmortizedCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Amortized Cost, Due after five years </link:label>
<link:label xml:lang="en-US" xlink:label="onto_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveYearsAmortizedCost_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Available For Sale Securities Debt Maturities After Five Years Amortized Cost </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Fair Value, Due within one year </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Available For Sale Securities Debt Maturities Within One Year Fair Value </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Fair Value, Due after one through five years </link:label>
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<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Available For Sale Securities Debt Maturities After One Through Five Years Fair Value </link:label>
<link:label xml:lang="en-US" xlink:label="onto_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveYearsFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Fair Value, Due after five years </link:label>
<link:label xml:lang="en-US" xlink:label="onto_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveYearsFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Available For Sale Securities Debt Maturities After Five Years Fair Value </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Fair Value, Total marketable securities </link:label>
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<link:label xml:lang="en-US" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> In Unrealized Loss Position For Less Than 12 Months, Fair Value </link:label>
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<link:label xml:lang="en-US" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> In Unrealized Loss Position For Greater Than 12 Months, Fair Value </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses </link:label>
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<link:label xml:lang="en-US" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeNotionalAmount" xlink:type="locator" xlink:label="us-gaap_DerivativeNotionalAmount"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DerivativeNotionalAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Notional amount </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeNotionalAmount" xlink:to="us-gaap_DerivativeNotionalAmount_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DerivativeNotionalAmount_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Derivative Notional Amount </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueNetAssetLiability" xlink:type="locator" xlink:label="us-gaap_FairValueNetAssetLiability"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueNetAssetLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Fair value of liability </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueNetAssetLiability" xlink:to="us-gaap_FairValueNetAssetLiability_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FairValueNetAssetLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Fair Value Net Asset Liability </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_IntangibleAssetsAccumulatedAmortizationExcludingGoodwill" xlink:type="locator" xlink:label="onto_IntangibleAssetsAccumulatedAmortizationExcludingGoodwill"/>
<link:label xml:lang="en-US" xlink:label="onto_IntangibleAssetsAccumulatedAmortizationExcludingGoodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Intangible assets accumulated amortization excluding goodwill </link:label>
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<link:label xml:lang="en-US" xlink:label="onto_IdentifiableIntangibleAssetsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Identifiable Intangible Assets [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_IdentifiableIntangibleAssetsAbstract" xlink:to="onto_IdentifiableIntangibleAssetsAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_IdentifiableIntangibleAssetsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Identifiable Intangible Assets [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
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<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Finite Lived Intangible Assets [Table] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
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<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
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<link:label xml:lang="en-US" xlink:label="us-gaap_DevelopedTechnologyRightsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Developed technology [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DevelopedTechnologyRightsMember" xlink:to="us-gaap_DevelopedTechnologyRightsMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DevelopedTechnologyRightsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Developed Technology Rights [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CustomerRelationshipsMember" xlink:type="locator" xlink:label="us-gaap_CustomerRelationshipsMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CustomerRelationshipsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Customer and distributor relationships [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CustomerRelationshipsMember" xlink:to="us-gaap_CustomerRelationshipsMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CustomerRelationshipsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Customer Relationships [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TrademarksAndTradeNamesMember" xlink:type="locator" xlink:label="us-gaap_TrademarksAndTradeNamesMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TrademarksAndTradeNamesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Trademarks and trade names [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TrademarksAndTradeNamesMember" xlink:to="us-gaap_TrademarksAndTradeNamesMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TrademarksAndTradeNamesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Trademarks And Trade Names [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Finite Lived Intangible Assets [Line Items] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetsLineItems_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets [Line Items] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Finite-lived intangibles assets, Gross Carrying Amount </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsGross" xlink:to="us-gaap_FiniteLivedIntangibleAssetsGross_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets Gross </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Finite-lived intangibles assets, Accumulated Amortization </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets Accumulated Amortization </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Finite-lived intangibles assets, Net </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsNet" xlink:to="us-gaap_FiniteLivedIntangibleAssetsNet_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets Net </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IntangibleAssetsGrossExcludingGoodwill" xlink:type="locator" xlink:label="us-gaap_IntangibleAssetsGrossExcludingGoodwill"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IntangibleAssetsGrossExcludingGoodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Identifiable intangibles assets, Gross Carrying Amount </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IntangibleAssetsGrossExcludingGoodwill" xlink:to="us-gaap_IntangibleAssetsGrossExcludingGoodwill_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_IntangibleAssetsGrossExcludingGoodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Intangible Assets Gross Excluding Goodwill </link:label>
<link:label xml:lang="en-US" xlink:label="onto_IntangibleAssetsAccumulatedAmortizationExcludingGoodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Identifiable intangibles assets, Accumulated Amortization </link:label>
<link:label xml:lang="en-US" xlink:label="onto_IntangibleAssetsAccumulatedAmortizationExcludingGoodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Intangible Assets Accumulated Amortization Excluding Goodwill </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Identifiable intangibles assets, Net </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets Future Amortization Expense [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:to="us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> 2022 (remainder) </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets Amortization Expense Remainder Of Fiscal Year </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> 2023 </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets Amortization Expense Next Twelve Months </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> 2024 </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets Amortization Expense Year Two </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> 2025 </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets Amortization Expense Year Three </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> 2026 </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets Amortization Expense Year Four </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> 2027 </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets Amortization Expense Year Five </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Thereafter </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Finite Lived Intangible Assets Amortization Expense After Year Five </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_InventoryDetailsAbstract" xlink:type="locator" xlink:label="onto_InventoryDetailsAbstract"/>
<link:label xml:lang="en-US" xlink:label="onto_InventoryDetailsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Inventory Details [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_InventoryDetailsAbstract" xlink:to="onto_InventoryDetailsAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_InventoryDetailsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Inventory Details [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InventoryRawMaterialsNetOfReserves" xlink:type="locator" xlink:label="us-gaap_InventoryRawMaterialsNetOfReserves"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InventoryRawMaterialsNetOfReserves_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Materials </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryRawMaterialsNetOfReserves" xlink:to="us-gaap_InventoryRawMaterialsNetOfReserves_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InventoryRawMaterialsNetOfReserves_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Inventory Raw Materials Net Of Reserves </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InventoryWorkInProcessNetOfReserves" xlink:type="locator" xlink:label="us-gaap_InventoryWorkInProcessNetOfReserves"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InventoryWorkInProcessNetOfReserves_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Work-in-process </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryWorkInProcessNetOfReserves" xlink:to="us-gaap_InventoryWorkInProcessNetOfReserves_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InventoryWorkInProcessNetOfReserves_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Inventory Work In Process Net Of Reserves </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:type="locator" xlink:label="us-gaap_InventoryFinishedGoodsNetOfReserves"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InventoryFinishedGoodsNetOfReserves_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Finished goods </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InventoryFinishedGoodsNetOfReserves" xlink:to="us-gaap_InventoryFinishedGoodsNetOfReserves_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_InventoryFinishedGoodsNetOfReserves_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Inventory Finished Goods Net Of Reserves </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_InventoryNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total inventories, net </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Property Plant And Equipment [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentAbstract" xlink:to="us-gaap_PropertyPlantAndEquipmentAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule Of Property Plant And Equipment [Table] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Property Plant And Equipment [Table] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Long-Lived Tangible Asset </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Property Plant And Equipment By Type [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Long-Lived Tangible Asset </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Property Plant And Equipment Type [Domain] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LandAndBuildingMember" xlink:type="locator" xlink:label="us-gaap_LandAndBuildingMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LandAndBuildingMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Land and building [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LandAndBuildingMember" xlink:to="us-gaap_LandAndBuildingMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LandAndBuildingMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Land And Building [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MachineryAndEquipmentMember" xlink:type="locator" xlink:label="us-gaap_MachineryAndEquipmentMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_MachineryAndEquipmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Machinery and equipment [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MachineryAndEquipmentMember" xlink:to="us-gaap_MachineryAndEquipmentMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_MachineryAndEquipmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Machinery And Equipment [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FurnitureAndFixturesMember" xlink:type="locator" xlink:label="us-gaap_FurnitureAndFixturesMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Furniture and fixtures [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FurnitureAndFixturesMember" xlink:to="us-gaap_FurnitureAndFixturesMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Furniture And Fixtures [Member] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_ComputerEquipmentAndSoftwareMember" xlink:type="locator" xlink:label="onto_ComputerEquipmentAndSoftwareMember"/>
<link:label xml:lang="en-US" xlink:label="onto_ComputerEquipmentAndSoftwareMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Computer equipment and software [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_ComputerEquipmentAndSoftwareMember" xlink:to="onto_ComputerEquipmentAndSoftwareMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_ComputerEquipmentAndSoftwareMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Computer Equipment And Software [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseholdImprovementsMember" xlink:type="locator" xlink:label="us-gaap_LeaseholdImprovementsMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LeaseholdImprovementsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Leasehold improvements [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseholdImprovementsMember" xlink:to="us-gaap_LeaseholdImprovementsMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LeaseholdImprovementsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Leasehold Improvements [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Property Plant And Equipment [Line Items] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentLineItems_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Property Plant And Equipment [Line Items] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentGross"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Property, plant and equipment, gross </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentGross" xlink:to="us-gaap_PropertyPlantAndEquipmentGross_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Property Plant And Equipment Gross </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Accumulated depreciation and amortization </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accumulated Depreciation Depletion And Amortization Property Plant And Equipment </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total property, plant and equipment, net </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsAbstract" xlink:type="locator" xlink:label="us-gaap_OtherAssetsAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherAssetsAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Assets [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherAssetsAbstract" xlink:to="us-gaap_OtherAssetsAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Operating lease right-of-use assets </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseRightOfUseAsset" xlink:to="us-gaap_OperatingLeaseRightOfUseAsset_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Operating Lease Right Of Use Asset </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsMiscellaneousNoncurrent" xlink:type="locator" xlink:label="us-gaap_OtherAssetsMiscellaneousNoncurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherAssetsMiscellaneousNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Other </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherAssetsMiscellaneousNoncurrent" xlink:to="us-gaap_OtherAssetsMiscellaneousNoncurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherAssetsMiscellaneousNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Assets Miscellaneous Noncurrent </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total other assets </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccruedLiabilitiesCurrentAbstract" xlink:type="locator" xlink:label="us-gaap_AccruedLiabilitiesCurrentAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccruedLiabilitiesCurrentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accrued Liabilities Current [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccruedLiabilitiesCurrentAbstract" xlink:to="us-gaap_AccruedLiabilitiesCurrentAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Payroll and related expenses </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:to="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Employee Related Liabilities Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProductWarrantyAccrualClassifiedCurrent" xlink:type="locator" xlink:label="us-gaap_ProductWarrantyAccrualClassifiedCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProductWarrantyAccrualClassifiedCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Warranty </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProductWarrantyAccrualClassifiedCurrent" xlink:to="us-gaap_ProductWarrantyAccrualClassifiedCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProductWarrantyAccrualClassifiedCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Product Warranty Accrual Classified Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_OtherAccruedLiabilitiesCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherAccruedLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Other </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherAccruedLiabilitiesCurrent" xlink:to="us-gaap_OtherAccruedLiabilitiesCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherAccruedLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Accrued Liabilities Current </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccruedLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total accrued liabilities </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilitiesCurrentAbstract" xlink:type="locator" xlink:label="us-gaap_OtherLiabilitiesCurrentAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherLiabilitiesCurrentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Liabilities Current [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherLiabilitiesCurrentAbstract" xlink:to="us-gaap_OtherLiabilitiesCurrentAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerRefundLiabilityCurrent" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerRefundLiabilityCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerRefundLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Customer deposits </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerRefundLiabilityCurrent" xlink:to="us-gaap_ContractWithCustomerRefundLiabilityCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerRefundLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Contract With Customer Refund Liability Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Current operating lease obligations </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseLiabilityCurrent" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Operating Lease Liability Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TaxesPayableCurrent" xlink:type="locator" xlink:label="us-gaap_TaxesPayableCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TaxesPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Income tax payable </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TaxesPayableCurrent" xlink:to="us-gaap_TaxesPayableCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TaxesPayableCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Taxes Payable Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccruedProfessionalFeesCurrent" xlink:type="locator" xlink:label="us-gaap_AccruedProfessionalFeesCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccruedProfessionalFeesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accrued professional fees </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccruedProfessionalFeesCurrent" xlink:to="us-gaap_AccruedProfessionalFeesCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccruedProfessionalFeesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accrued Professional Fees Current </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherSundryLiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_OtherSundryLiabilitiesCurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherSundryLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Other </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherSundryLiabilitiesCurrent" xlink:to="us-gaap_OtherSundryLiabilitiesCurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherSundryLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Sundry Liabilities Current </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherLiabilitiesCurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total other current liabilities </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_UnrecognizedTaxBenefitsIncludingInterestNoncurrent" xlink:type="locator" xlink:label="onto_UnrecognizedTaxBenefitsIncludingInterestNoncurrent"/>
<link:label xml:lang="en-US" xlink:label="onto_UnrecognizedTaxBenefitsIncludingInterestNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Unrecognized tax benefits including interest noncurrent. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_UnrecognizedTaxBenefitsIncludingInterestNoncurrent" xlink:to="onto_UnrecognizedTaxBenefitsIncludingInterestNoncurrent_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilitiesNoncurrentAbstract" xlink:type="locator" xlink:label="us-gaap_OtherLiabilitiesNoncurrentAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherLiabilitiesNoncurrentAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Liabilities Noncurrent [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherLiabilitiesNoncurrentAbstract" xlink:to="us-gaap_OtherLiabilitiesNoncurrentAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Non-current operating lease obligations </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Operating Lease Liability Noncurrent </link:label>
<link:label xml:lang="en-US" xlink:label="onto_UnrecognizedTaxBenefitsIncludingInterestNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Unrecognized tax benefits (including interest) </link:label>
<link:label xml:lang="en-US" xlink:label="onto_UnrecognizedTaxBenefitsIncludingInterestNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Unrecognized Tax Benefits Including Interest Noncurrent </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList" xlink:type="locator" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Operating Lease Liability Noncurrent Statement Of Financial Position Extensible List </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Deferred revenue </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:to="us-gaap_ContractWithCustomerLiabilityNoncurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Contract With Customer Liability Noncurrent </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherSundryLiabilitiesNoncurrent" xlink:type="locator" xlink:label="us-gaap_OtherSundryLiabilitiesNoncurrent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherSundryLiabilitiesNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Other </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherSundryLiabilitiesNoncurrent" xlink:to="us-gaap_OtherSundryLiabilitiesNoncurrent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherSundryLiabilitiesNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Sundry Liabilities Noncurrent </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total other non-current liabilities </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_ProceedsFromAccountsReceivable" xlink:type="locator" xlink:label="onto_ProceedsFromAccountsReceivable"/>
<link:label xml:lang="en-US" xlink:label="onto_ProceedsFromAccountsReceivable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Proceeds from accounts receivable. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_ProceedsFromAccountsReceivable" xlink:to="onto_ProceedsFromAccountsReceivable_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_DueFromUnrelatedThirdParties" xlink:type="locator" xlink:label="onto_DueFromUnrelatedThirdParties"/>
<link:label xml:lang="en-US" xlink:label="onto_DueFromUnrelatedThirdParties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Due from unrelated third Parties. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_DueFromUnrelatedThirdParties" xlink:to="onto_DueFromUnrelatedThirdParties_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_CommitmentsAndContingenciesLineItems" xlink:type="locator" xlink:label="onto_CommitmentsAndContingenciesLineItems"/>
<link:label xml:lang="en-US" xlink:label="onto_CommitmentsAndContingenciesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Commitments and contingencies line items. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_CommitmentsAndContingenciesLineItems" xlink:to="onto_CommitmentsAndContingenciesLineItems_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_CommitmentsAndContingenciesTable" xlink:type="locator" xlink:label="onto_CommitmentsAndContingenciesTable"/>
<link:label xml:lang="en-US" xlink:label="onto_CommitmentsAndContingenciesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Commitments and contingencies table. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_CommitmentsAndContingenciesTable" xlink:to="onto_CommitmentsAndContingenciesTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_CommitmentsAndContingenciesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Commitments And Contingencies [Table] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_CommitmentsAndContingenciesTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Commitments And Contingencies [Table] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_CommitmentsAndContingenciesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Commitments And Contingencies [Line Items] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_CommitmentsAndContingenciesLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Commitments And Contingencies [Line Items] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_ProceedsFromAccountsReceivable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Sold receivables amount </link:label>
<link:label xml:lang="en-US" xlink:label="onto_ProceedsFromAccountsReceivable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Proceeds From Accounts Receivable </link:label>
<link:label xml:lang="en-US" xlink:label="onto_DueFromUnrelatedThirdParties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Due from unrelated third parties </link:label>
<link:label xml:lang="en-US" xlink:label="onto_DueFromUnrelatedThirdParties_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Due From Unrelated Third Parties </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_IntellectualPropertyIndemnificationObligations" xlink:type="locator" xlink:label="onto_IntellectualPropertyIndemnificationObligations"/>
<link:label xml:lang="en-US" xlink:label="onto_IntellectualPropertyIndemnificationObligations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Intellectual property indemnification obligation. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_IntellectualPropertyIndemnificationObligations" xlink:to="onto_IntellectualPropertyIndemnificationObligations_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_IntellectualPropertyIndemnificationObligations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Liabilities recorded for obligations </link:label>
<link:label xml:lang="en-US" xlink:label="onto_IntellectualPropertyIndemnificationObligations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Intellectual Property Indemnification Obligations </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_ProductWarrantyAccrualWarrantyPeriod" xlink:type="locator" xlink:label="onto_ProductWarrantyAccrualWarrantyPeriod"/>
<link:label xml:lang="en-US" xlink:label="onto_ProductWarrantyAccrualWarrantyPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Product warranty accrual warranty period. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_ProductWarrantyAccrualWarrantyPeriod" xlink:to="onto_ProductWarrantyAccrualWarrantyPeriod_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_ProductWarrantyAccrualWarrantyPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Warranty period </link:label>
<link:label xml:lang="en-US" xlink:label="onto_ProductWarrantyAccrualWarrantyPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Product Warranty Accrual Warranty Period </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StandardProductWarrantyAccrual" xlink:type="locator" xlink:label="us-gaap_StandardProductWarrantyAccrual"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StandardProductWarrantyAccrual_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel"> Balance, beginning of the period </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StandardProductWarrantyAccrual" xlink:to="us-gaap_StandardProductWarrantyAccrual_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StandardProductWarrantyAccrual_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Standard Product Warranty Accrual </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProductWarrantyAccrualWarrantiesIssued" xlink:type="locator" xlink:label="us-gaap_ProductWarrantyAccrualWarrantiesIssued"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProductWarrantyAccrualWarrantiesIssued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accruals </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProductWarrantyAccrualWarrantiesIssued" xlink:to="us-gaap_ProductWarrantyAccrualWarrantiesIssued_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProductWarrantyAccrualWarrantiesIssued_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Product Warranty Accrual Warranties Issued </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StandardProductWarrantyAccrualAdditionsFromBusinessAcquisition" xlink:type="locator" xlink:label="us-gaap_StandardProductWarrantyAccrualAdditionsFromBusinessAcquisition"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StandardProductWarrantyAccrualAdditionsFromBusinessAcquisition_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Warranty liability assumed in acquisition </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StandardProductWarrantyAccrualAdditionsFromBusinessAcquisition" xlink:to="us-gaap_StandardProductWarrantyAccrualAdditionsFromBusinessAcquisition_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StandardProductWarrantyAccrualAdditionsFromBusinessAcquisition_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Standard Product Warranty Accrual Additions From Business Acquisition </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProductWarrantyAccrualPayments" xlink:type="locator" xlink:label="us-gaap_ProductWarrantyAccrualPayments"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProductWarrantyAccrualPayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Usage </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProductWarrantyAccrualPayments" xlink:to="us-gaap_ProductWarrantyAccrualPayments_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProductWarrantyAccrualPayments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Product Warranty Accrual Payments </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_StandardProductWarrantyAccrual_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel"> Balance, end of the period </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_MaximumBorrowingCapacityPercentageOfEligibleSecuritiesHeldAtLineOfCreditAccessed" xlink:type="locator" xlink:label="onto_MaximumBorrowingCapacityPercentageOfEligibleSecuritiesHeldAtLineOfCreditAccessed"/>
<link:label xml:lang="en-US" xlink:label="onto_MaximumBorrowingCapacityPercentageOfEligibleSecuritiesHeldAtLineOfCreditAccessed_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Maximum borrowing capacity percentage of eligible securities held at line of credit accessed. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_MaximumBorrowingCapacityPercentageOfEligibleSecuritiesHeldAtLineOfCreditAccessed" xlink:to="onto_MaximumBorrowingCapacityPercentageOfEligibleSecuritiesHeldAtLineOfCreditAccessed_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_MaximumBorrowingCapacityPercentageOfEligibleSecuritiesHeldAtLineOfCreditAccessed_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Percentage of maximum borrowing capacity of value of eligible securities </link:label>
<link:label xml:lang="en-US" xlink:label="onto_MaximumBorrowingCapacityPercentageOfEligibleSecuritiesHeldAtLineOfCreditAccessed_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Maximum Borrowing Capacity Percentage Of Eligible Securities Held At Line Of Credit Accessed </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Available line of credit </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:to="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Line Of Credit Facility Remaining Borrowing Capacity </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Available interest rate on line of credit </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd" xlink:to="us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Line Of Credit Facility Interest Rate At Period End </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:type="locator" xlink:label="us-gaap_DisaggregationOfRevenueTable"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DisaggregationOfRevenueTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Disaggregation Of Revenue [Table] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DisaggregationOfRevenueTable" xlink:to="us-gaap_DisaggregationOfRevenueTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DisaggregationOfRevenueTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Disaggregation Of Revenue [Table] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis" xlink:type="locator" xlink:label="us-gaap_TimingOfTransferOfGoodOrServiceAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TimingOfTransferOfGoodOrServiceAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Timing of Transfer of Good or Service </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TimingOfTransferOfGoodOrServiceAxis" xlink:to="us-gaap_TimingOfTransferOfGoodOrServiceAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TimingOfTransferOfGoodOrServiceAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Timing Of Transfer Of Good Or Service [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain" xlink:type="locator" xlink:label="us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TimingOfTransferOfGoodOrServiceDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Timing of Transfer of Good or Service </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TimingOfTransferOfGoodOrServiceDomain" xlink:to="us-gaap_TimingOfTransferOfGoodOrServiceDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TimingOfTransferOfGoodOrServiceDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Timing Of Transfer Of Good Or Service [Domain] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransferredAtPointInTimeMember" xlink:type="locator" xlink:label="us-gaap_TransferredAtPointInTimeMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TransferredAtPointInTimeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Transferred at Point in Time [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TransferredAtPointInTimeMember" xlink:to="us-gaap_TransferredAtPointInTimeMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TransferredAtPointInTimeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Transferred At Point In Time [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransferredOverTimeMember" xlink:type="locator" xlink:label="us-gaap_TransferredOverTimeMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TransferredOverTimeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Transferred over Time [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TransferredOverTimeMember" xlink:to="us-gaap_TransferredOverTimeMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_TransferredOverTimeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Transferred Over Time [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:type="locator" xlink:label="us-gaap_DisaggregationOfRevenueLineItems"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DisaggregationOfRevenueLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Disaggregation Of Revenue [Line Items] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DisaggregationOfRevenueLineItems" xlink:to="us-gaap_DisaggregationOfRevenueLineItems_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DisaggregationOfRevenueLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Disaggregation Of Revenue [Line Items] </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Total revenue </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityNoncurrent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveVerboseLabel"> Long-term deferred revenue </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_ContractWithCustomerLiabilityRevenueRecognizedIncludingAdditions" xlink:type="locator" xlink:label="onto_ContractWithCustomerLiabilityRevenueRecognizedIncludingAdditions"/>
<link:label xml:lang="en-US" xlink:label="onto_ContractWithCustomerLiabilityRevenueRecognizedIncludingAdditions_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Contract with customer liability revenue recognized including additions. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_ContractWithCustomerLiabilityRevenueRecognizedIncludingAdditions" xlink:to="onto_ContractWithCustomerLiabilityRevenueRecognizedIncludingAdditions_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredRevenueDisclosureAbstract" xlink:type="locator" xlink:label="us-gaap_DeferredRevenueDisclosureAbstract"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DeferredRevenueDisclosureAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Deferred Revenue Disclosure [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredRevenueDisclosureAbstract" xlink:to="us-gaap_DeferredRevenueDisclosureAbstract_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerLiability" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiability"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel"> Balance, beginning of the period </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiability" xlink:to="us-gaap_ContractWithCustomerLiability_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Contract With Customer Liability </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Deferred revenue assumed in acquisition </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination" xlink:to="us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityIncreaseDecreaseForContractAcquiredInBusinessCombination_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Contract With Customer Liability Increase Decrease For Contract Acquired In Business Combination </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Deferral of revenue </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress" xlink:to="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Contract With Customer Liability Cumulative Catch Up Adjustment To Revenue Change In Measure Of Progress </link:label>
<link:label xml:lang="en-US" xlink:label="onto_ContractWithCustomerLiabilityRevenueRecognizedIncludingAdditions_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Recognition of deferred revenue </link:label>
<link:label xml:lang="en-US" xlink:label="onto_ContractWithCustomerLiabilityRevenueRecognizedIncludingAdditions_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Contract With Customer Liability Revenue Recognized Including Additions </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_ContractWithCustomerLiability_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel"> Balance, end of the period </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_RestrictedStockUnitsActivityAbstract" xlink:type="locator" xlink:label="onto_RestrictedStockUnitsActivityAbstract"/>
<link:label xml:lang="en-US" xlink:label="onto_RestrictedStockUnitsActivityAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Restricted Stock Units Activity [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_RestrictedStockUnitsActivityAbstract" xlink:to="onto_RestrictedStockUnitsActivityAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_RestrictedStockUnitsActivityAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Restricted Stock Units Activity [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis" xlink:type="locator" xlink:label="us-gaap_AwardTypeAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AwardTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Award Type </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_AwardTypeAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AwardTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Award Type [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Award Type </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:type="locator" xlink:label="us-gaap_RestrictedStockUnitsRSUMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_RestrictedStockUnitsRSUMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Restricted Stock Units (RSUs) [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RestrictedStockUnitsRSUMember" xlink:to="us-gaap_RestrictedStockUnitsRSUMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_RestrictedStockUnitsRSUMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Restricted Stock Units R S U [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Share Based Compensation Arrangement By Share Based Payment Award [Line Items] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangement By Share Based Payment Award [Line Items] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Activity for RSUs [Roll Forward] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Roll Forward </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel"> Number of Shares, Beginning balance (in shares) </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Number of Shares, Granted (in shares) </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Number of Shares, Vested (in shares) </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel"> Number of Shares, Forfeited (in shares) </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeited In Period </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel"> Number of Shares, Ending balance (in shares) </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Weighted Average Grant Date Fair Value for RSUs [Roll Forward] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value Roll Forward </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel"> Weighted Average Grant Date Fair Value, Beginning balance (in dollars per share) </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Weighted Average Grant Date Fair Value, Granted (in dollars per share) </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Weighted Average Grant Date Fair Value </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Weighted Average Grant Date Fair Value, Vested (in dollars per share) </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Weighted Average Grant Date Fair Value </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Weighted Average Grant Date Fair Value, Forfeited (in dollars per share) </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeitures Weighted Average Grant Date Fair Value </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel"> Weighted Average Grant Date Fair Value, Ending balance (in dollars per share) </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_RestrictedStockUnitsServiceBasedRSUsMember" xlink:type="locator" xlink:label="onto_RestrictedStockUnitsServiceBasedRSUsMember"/>
<link:label xml:lang="en-US" xlink:label="onto_RestrictedStockUnitsServiceBasedRSUsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Restricted Stock Units, Service-Based RSUs. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_RestrictedStockUnitsServiceBasedRSUsMember" xlink:to="onto_RestrictedStockUnitsServiceBasedRSUsMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_RestrictedStockUnitsServiceBasedRSUsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Restricted Stock Units, Service-Based RSUs [Member] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_RestrictedStockUnitsServiceBasedRSUsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Restricted Stock Units Service Based R S Us [Member] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_PerformanceRestrictedStockUnitsMember" xlink:type="locator" xlink:label="onto_PerformanceRestrictedStockUnitsMember"/>
<link:label xml:lang="en-US" xlink:label="onto_PerformanceRestrictedStockUnitsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Performance restricted stock units. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_PerformanceRestrictedStockUnitsMember" xlink:to="onto_PerformanceRestrictedStockUnitsMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_PerformanceRestrictedStockUnitsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Performance Restricted Stock Units (PRSUs) [Member] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_PerformanceRestrictedStockUnitsMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Performance Restricted Stock Units [Member] </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Number of nonvested shares outstanding </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Weighted average grant-date fair value per share </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Total unrecognized compensation cost related to restricted stock units granted </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Unrecognized compensation cost related to restricted stock units, weighted average period </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_OtherExpenseIncome" xlink:type="locator" xlink:label="onto_OtherExpenseIncome"/>
<link:label xml:lang="en-US" xlink:label="onto_OtherExpenseIncome_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Other (expense) income. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_OtherExpenseIncome" xlink:to="onto_OtherExpenseIncome_lbl"/>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:type="locator" xlink:label="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Foreign currency exchange losses, net </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:to="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Foreign Currency Transaction Gain Loss Before Tax </link:label>
<link:label xml:lang="en-US" xlink:label="onto_OtherExpenseIncome_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Other </link:label>
<link:label xml:lang="en-US" xlink:label="onto_OtherExpenseIncome_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Other Expense Income </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_OtherNonoperatingIncomeExpense_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Total other expense, net </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Income before income taxes </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Effective tax rate </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Effective Income Tax Rate Continuing Operations </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Deferred tax assets, valuation allowance </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsValuationAllowance" xlink:to="us-gaap_DeferredTaxAssetsValuationAllowance_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Deferred Tax Assets Valuation Allowance </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Basic earnings per share - weighted average shares outstanding </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Employee stock options, employee stock purchase grants and restricted stock units - dilutive shares </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:to="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Weighted Average Number Diluted Shares Outstanding Adjustment </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel"> Diluted earnings per share - weighted average shares outstanding </link:label>
<link:label xml:lang="en-US" xlink:label="onto_EarningsPerSharesBasicAndDilutedAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Earnings per share: </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Basic </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Diluted </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_AccumulatedOtherComprehensiveLossAbstract" xlink:type="locator" xlink:label="onto_AccumulatedOtherComprehensiveLossAbstract"/>
<link:label xml:lang="en-US" xlink:label="onto_AccumulatedOtherComprehensiveLossAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Accumulated Other Comprehensive Loss [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_AccumulatedOtherComprehensiveLossAbstract" xlink:to="onto_AccumulatedOtherComprehensiveLossAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_AccumulatedOtherComprehensiveLossAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accumulated Other Comprehensive Loss [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accumulated Other Comprehensive Income Loss [Table] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accumulated Other Comprehensive Income Loss [Table] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedTranslationAdjustmentMember" xlink:type="locator" xlink:label="us-gaap_AccumulatedTranslationAdjustmentMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedTranslationAdjustmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accumulated Foreign Currency Translation Adjustments [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedTranslationAdjustmentMember" xlink:to="us-gaap_AccumulatedTranslationAdjustmentMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedTranslationAdjustmentMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accumulated Translation Adjustment [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:type="locator" xlink:label="us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accumulated Net Unrealized Losses on Available-for-sale Marketable Securities [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:to="us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accumulated Net Unrealized Investment Gain Loss [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Accumulated Other Comprehensive Income Loss [Line Items] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Accumulated Other Comprehensive Income Loss [Line Items] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent" xlink:type="locator" xlink:label="us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Net current period other comprehensive loss </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent" xlink:to="us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Oci Before Reclassifications Net Of Tax Attributable To Parent </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent" xlink:type="locator" xlink:label="us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Reclassifications </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent" xlink:to="us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Reclassification From Aoci Current Period Net Of Tax Attributable To Parent </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_TaxEffectMarketableSecurities" xlink:type="locator" xlink:label="onto_TaxEffectMarketableSecurities"/>
<link:label xml:lang="en-US" xlink:label="onto_TaxEffectMarketableSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> tax effects on net income of amounts recorded in other comprehensive loss for net unrealized losses on available-for-sale marketable securities. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_TaxEffectMarketableSecurities" xlink:to="onto_TaxEffectMarketableSecurities_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_TaxEffectForeignCurrencyTranslation" xlink:type="locator" xlink:label="onto_TaxEffectForeignCurrencyTranslation"/>
<link:label xml:lang="en-US" xlink:label="onto_TaxEffectForeignCurrencyTranslation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> tax effects on net income of amounts recorded in other comprehensive loss for foreign currency translation adjustments </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_TaxEffectForeignCurrencyTranslation" xlink:to="onto_TaxEffectForeignCurrencyTranslation_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_TaxEffectMarketableSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Tax Effect Marketable Securities </link:label>
<link:label xml:lang="en-US" xlink:label="onto_TaxEffectMarketableSecurities_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Tax Effect Marketable Securities </link:label>
<link:label xml:lang="en-US" xlink:label="onto_TaxEffectForeignCurrencyTranslation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Tax Effect Foreign Currency Translation </link:label>
<link:label xml:lang="en-US" xlink:label="onto_TaxEffectForeignCurrencyTranslation_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Tax Effect Foreign Currency Translation </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NumberOfReportableSegments" xlink:type="locator" xlink:label="us-gaap_NumberOfReportableSegments"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Number of reportable segments </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NumberOfReportableSegments" xlink:to="us-gaap_NumberOfReportableSegments_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Number Of Reportable Segments </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_SegmentReportingByBusinessUnitAbstract" xlink:type="locator" xlink:label="onto_SegmentReportingByBusinessUnitAbstract"/>
<link:label xml:lang="en-US" xlink:label="onto_SegmentReportingByBusinessUnitAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Segment reporting by business unit. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_SegmentReportingByBusinessUnitAbstract" xlink:to="onto_SegmentReportingByBusinessUnitAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_SegmentReportingByBusinessUnitAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Segment Reporting By Business Unit [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Schedule Of Segment Reporting Information By Segment [Table] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Schedule Of Segment Reporting Information By Segment [Table] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis" xlink:type="locator" xlink:label="srt_ProductOrServiceAxis"/>
<link:label xml:lang="en-US" xlink:label="srt_ProductOrServiceAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Product and Service </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ProductOrServiceAxis" xlink:to="srt_ProductOrServiceAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="srt_ProductOrServiceAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Product Or Service [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain" xlink:type="locator" xlink:label="srt_ProductsAndServicesDomain"/>
<link:label xml:lang="en-US" xlink:label="srt_ProductsAndServicesDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Product and Service </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ProductsAndServicesDomain" xlink:to="srt_ProductsAndServicesDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="srt_ProductsAndServicesDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Products And Services [Domain] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_SystemsAndSoftwareRevenueMember" xlink:type="locator" xlink:label="onto_SystemsAndSoftwareRevenueMember"/>
<link:label xml:lang="en-US" xlink:label="onto_SystemsAndSoftwareRevenueMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Systems and software revenue. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_SystemsAndSoftwareRevenueMember" xlink:to="onto_SystemsAndSoftwareRevenueMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_SystemsAndSoftwareRevenueMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Systems and Software [Member] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_SystemsAndSoftwareRevenueMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Systems And Software Revenue [Member] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_PartsRevenueMember" xlink:type="locator" xlink:label="onto_PartsRevenueMember"/>
<link:label xml:lang="en-US" xlink:label="onto_PartsRevenueMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Parts revenue. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_PartsRevenueMember" xlink:to="onto_PartsRevenueMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_PartsRevenueMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel"> Parts Revenue [Member] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_PartsRevenueMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Parts Revenue [Member] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_ServiceRevenueMember" xlink:type="locator" xlink:label="onto_ServiceRevenueMember"/>
<link:label xml:lang="en-US" xlink:label="onto_ServiceRevenueMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Service revenue. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_ServiceRevenueMember" xlink:to="onto_ServiceRevenueMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_ServiceRevenueMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Service Revenue [Member] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_ServiceRevenueMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Service Revenue [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskByBenchmarkAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskByBenchmarkAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Concentration Risk Benchmark </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:to="us-gaap_ConcentrationRiskByBenchmarkAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskByBenchmarkAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Concentration Risk By Benchmark [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskBenchmarkDomain"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskBenchmarkDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Concentration Risk Benchmark </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskBenchmarkDomain" xlink:to="us-gaap_ConcentrationRiskBenchmarkDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskBenchmarkDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Concentration Risk Benchmark [Domain] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesRevenueNetMember" xlink:type="locator" xlink:label="us-gaap_SalesRevenueNetMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SalesRevenueNetMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Sales [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SalesRevenueNetMember" xlink:to="us-gaap_SalesRevenueNetMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SalesRevenueNetMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Sales Revenue Net [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskByTypeAxis"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskByTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Concentration Risk Type </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskByTypeAxis" xlink:to="us-gaap_ConcentrationRiskByTypeAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskByTypeAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Concentration Risk By Type [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskTypeDomain"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Concentration Risk Type </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskTypeDomain" xlink:to="us-gaap_ConcentrationRiskTypeDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskTypeDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Concentration Risk Type [Domain] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProductConcentrationRiskMember" xlink:type="locator" xlink:label="us-gaap_ProductConcentrationRiskMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProductConcentrationRiskMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Product [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProductConcentrationRiskMember" xlink:to="us-gaap_ProductConcentrationRiskMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ProductConcentrationRiskMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Product Concentration Risk [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:type="locator" xlink:label="us-gaap_SegmentReportingInformationLineItems"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingInformationLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Segment Reporting Information [Line Items] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_SegmentReportingInformationLineItems_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_SegmentReportingInformationLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Segment Reporting Information [Line Items] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskPercentage1"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskPercentage1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Concentration risk, percentage </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskPercentage1" xlink:to="us-gaap_ConcentrationRiskPercentage1_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskPercentage1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Concentration Risk Percentage1 </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_GeographicReportingAbstract" xlink:type="locator" xlink:label="onto_GeographicReportingAbstract"/>
<link:label xml:lang="en-US" xlink:label="onto_GeographicReportingAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Geographic reporting [Abstract] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_GeographicReportingAbstract" xlink:to="onto_GeographicReportingAbstract_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_GeographicReportingAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Geographic Reporting [Abstract] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_StatementGeographicalAxis" xlink:type="locator" xlink:label="srt_StatementGeographicalAxis"/>
<link:label xml:lang="en-US" xlink:label="srt_StatementGeographicalAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Geographical </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_StatementGeographicalAxis" xlink:to="srt_StatementGeographicalAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="srt_StatementGeographicalAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Statement Geographical [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain" xlink:type="locator" xlink:label="srt_SegmentGeographicalDomain"/>
<link:label xml:lang="en-US" xlink:label="srt_SegmentGeographicalDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Geographical </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_SegmentGeographicalDomain" xlink:to="srt_SegmentGeographicalDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="srt_SegmentGeographicalDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Segment Geographical [Domain] </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_CN" xlink:type="locator" xlink:label="country_CN"/>
<link:label xml:lang="en-US" xlink:label="country_CN_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> China [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="country_CN" xlink:to="country_CN_lbl"/>
<link:label xml:lang="en-US" xlink:label="country_CN_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> CHINA </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_KR" xlink:type="locator" xlink:label="country_KR"/>
<link:label xml:lang="en-US" xlink:label="country_KR_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> South Korea [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="country_KR" xlink:to="country_KR_lbl"/>
<link:label xml:lang="en-US" xlink:label="country_KR_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> KOREA, REPUBLIC OF </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_TW" xlink:type="locator" xlink:label="country_TW"/>
<link:label xml:lang="en-US" xlink:label="country_TW_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Taiwan [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="country_TW" xlink:to="country_TW_lbl"/>
<link:label xml:lang="en-US" xlink:label="country_TW_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> TAIWAN </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_US" xlink:type="locator" xlink:label="country_US"/>
<link:label xml:lang="en-US" xlink:label="country_US_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> United States [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="country_US" xlink:to="country_US_lbl"/>
<link:label xml:lang="en-US" xlink:label="country_US_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> UNITED STATES </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EuropeMember" xlink:type="locator" xlink:label="srt_EuropeMember"/>
<link:label xml:lang="en-US" xlink:label="srt_EuropeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Europe [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_EuropeMember" xlink:to="srt_EuropeMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="srt_EuropeMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Europe [Member] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_SoutheastAsiaMember" xlink:type="locator" xlink:label="onto_SoutheastAsiaMember"/>
<link:label xml:lang="en-US" xlink:label="onto_SoutheastAsiaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Southeast Asia. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_SoutheastAsiaMember" xlink:to="onto_SoutheastAsiaMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_SoutheastAsiaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Southeast Asia [Member] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_SoutheastAsiaMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Southeast Asia [Member] </link:label>
<link:loc xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_JP" xlink:type="locator" xlink:label="country_JP"/>
<link:label xml:lang="en-US" xlink:label="country_JP_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Japan [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="country_JP" xlink:to="country_JP_lbl"/>
<link:label xml:lang="en-US" xlink:label="country_JP_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> JAPAN </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskTable" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskTable"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Concentration Risk [Table] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskTable" xlink:to="us-gaap_ConcentrationRiskTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Concentration Risk [Table] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:type="locator" xlink:label="us-gaap_CustomerConcentrationRiskMember"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CustomerConcentrationRiskMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Customer Concentration Risk </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CustomerConcentrationRiskMember" xlink:to="us-gaap_CustomerConcentrationRiskMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_CustomerConcentrationRiskMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Customer Concentration Risk [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MajorCustomersAxis" xlink:type="locator" xlink:label="srt_MajorCustomersAxis"/>
<link:label xml:lang="en-US" xlink:label="srt_MajorCustomersAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Customer </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MajorCustomersAxis" xlink:to="srt_MajorCustomersAxis_lbl"/>
<link:label xml:lang="en-US" xlink:label="srt_MajorCustomersAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Major Customers [Axis] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_NameOfMajorCustomerDomain" xlink:type="locator" xlink:label="srt_NameOfMajorCustomerDomain"/>
<link:label xml:lang="en-US" xlink:label="srt_NameOfMajorCustomerDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Customer </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_NameOfMajorCustomerDomain" xlink:to="srt_NameOfMajorCustomerDomain_lbl"/>
<link:label xml:lang="en-US" xlink:label="srt_NameOfMajorCustomerDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Name Of Major Customer [Domain] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_SKHynixIncMember" xlink:type="locator" xlink:label="onto_SKHynixIncMember"/>
<link:label xml:lang="en-US" xlink:label="onto_SKHynixIncMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> SK Hynix Inc. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_SKHynixIncMember" xlink:to="onto_SKHynixIncMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_SKHynixIncMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> SK Hynix Inc. [Member] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_SKHynixIncMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> S K Hynix Inc [Member] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_TaiwanSemiconductorManufacturingCompanyLimitedMember" xlink:type="locator" xlink:label="onto_TaiwanSemiconductorManufacturingCompanyLimitedMember"/>
<link:label xml:lang="en-US" xlink:label="onto_TaiwanSemiconductorManufacturingCompanyLimitedMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Taiwan semiconductor manufacturing company limited. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_TaiwanSemiconductorManufacturingCompanyLimitedMember" xlink:to="onto_TaiwanSemiconductorManufacturingCompanyLimitedMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_TaiwanSemiconductorManufacturingCompanyLimitedMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Taiwan Semiconductor Manufacturing Co. Ltd. [Member] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_TaiwanSemiconductorManufacturingCompanyLimitedMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Taiwan Semiconductor Manufacturing Company Limited [Member] </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_SamsungSemiconductorMember" xlink:type="locator" xlink:label="onto_SamsungSemiconductorMember"/>
<link:label xml:lang="en-US" xlink:label="onto_SamsungSemiconductorMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Samsung Semiconductor [Member] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_SamsungSemiconductorMember" xlink:to="onto_SamsungSemiconductorMember_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_SamsungSemiconductorMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Samsung Semiconductor [Member] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskLineItems" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskLineItems"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Concentration Risk [Line Items] </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskLineItems" xlink:to="us-gaap_ConcentrationRiskLineItems_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Concentration Risk [Line Items] </link:label>
<link:label xml:lang="en-US" xlink:label="us-gaap_ConcentrationRiskPercentage1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveLabel"> Customer concentration risk percentage </link:label>
<link:loc xlink:href="onto-20220702.xsd#onto_SharesRepurchaseAuthorizationLineItems" xlink:type="locator" xlink:label="onto_SharesRepurchaseAuthorizationLineItems"/>
<link:label xml:lang="en-US" xlink:label="onto_SharesRepurchaseAuthorizationLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Shares repurchase authorization. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_SharesRepurchaseAuthorizationLineItems" xlink:to="onto_SharesRepurchaseAuthorizationLineItems_lbl"/>
<link:loc xlink:href="onto-20220702.xsd#onto_SharesRepurchaseAuthorizationTable" xlink:type="locator" xlink:label="onto_SharesRepurchaseAuthorizationTable"/>
<link:label xml:lang="en-US" xlink:label="onto_SharesRepurchaseAuthorizationTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation"> Shares repurchase authorization. </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="onto_SharesRepurchaseAuthorizationTable" xlink:to="onto_SharesRepurchaseAuthorizationTable_lbl"/>
<link:label xml:lang="en-US" xlink:label="onto_SharesRepurchaseAuthorizationTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Shares Repurchase Authorization [Table] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_SharesRepurchaseAuthorizationTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Shares Repurchase Authorization [Table] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_SharesRepurchaseAuthorizationLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Shares Repurchase Authorization [Line Items] </link:label>
<link:label xml:lang="en-US" xlink:label="onto_SharesRepurchaseAuthorizationLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Shares Repurchase Authorization [Line Items] </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:type="locator" xlink:label="us-gaap_StockRepurchaseProgramAuthorizedAmount1"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockRepurchaseProgramAuthorizedAmount1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Stock repurchase, authorized amount </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:to="us-gaap_StockRepurchaseProgramAuthorizedAmount1_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockRepurchaseProgramAuthorizedAmount1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Stock Repurchase Program Authorized Amount1 </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:type="locator" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Shares purchased </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:to="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Stock Repurchased And Retired During Period Shares </link:label>
<link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" xlink:type="locator" xlink:label="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel"> Amount available for future repurchase </link:label>
<link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" xlink:to="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_lbl"/>
<link:label xml:lang="en-US" xlink:label="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label"> Stock Repurchase Program Remaining Authorized Repurchase Amount1 </link:label>
</link:labelLink>
</link:linkbase>

3 Previous Filings that this Filing References

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

 5/17/22  Onto Innovation Inc.              8-K:5,7,9   5/17/22   12:230K                                   ActiveDisclosure/FA
 1/27/20  Onto Innovation Inc.              8-K:5,9     1/22/20   11:444K                                   ActiveDisclosure/FA
10/28/19  Onto Innovation Inc.              8-K:2,3,5,710/25/19   17:666K                                   Donnelley … Solutions/FA
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