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<link:definition>1025 - Disclosure - Retirement Plans</link:definition>
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<link:definition>1026 - Disclosure - Stock-Based Compensation</link:definition>
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<link:definition>1027 - Disclosure - Savings Plan</link:definition>
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<link:definition>1028 - Disclosure - Income Taxes</link:definition>
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<link:definition>1029 - Disclosure - Operating Segment, Geographic and Significant Customer Information</link:definition>
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<link:definition>1030 - Disclosure - Stock Repurchase Program</link:definition>
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<link:definition>1032 - Disclosure - Supplementaryd Information</link:definition>
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<link:definition>1037 - Disclosure - Revenue (Tables)</link:definition>
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<link:definition>1042 - Disclosure - Debt (Tables)</link:definition>
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<link:definition>1048 - Disclosure - Income Taxes (Tables)</link:definition>
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<link:definition>1049 - Disclosure - Operating Segment, Geographic and Significant Customer Information (Tables)</link:definition>
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<link:definition>1050 - Disclosure - Supplementary Information (Tables)</link:definition>
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<link:definition>1051 - Disclosure - The Company - Additional information (Detail)</link:definition>
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<link:definition>1052 - Disclosure - Accounting Policies - Additional Information (Detail)</link:definition>
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<link:definition>1053 - Disclosure - Deferred Revenue and Customer Advances (Detail)</link:definition>
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<link:definition>1054 - Disclosure - Warranty Accrual Included in Other Accrued Liabilities (Detail)</link:definition>
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<link:definition>1055 - Disclosure - Extended Product Warranty of Short and Long-Term Deferred Revenue and Customer Advances (Detail)</link:definition>
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<link:definition>1057 - Disclosure - Useful Lives of Assets (Detail)</link:definition>
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<link:definition>1058 - Disclosure - Acquisitions and Investment in Other Company - Additional Information (Detail)</link:definition>
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<link:definition>1059 - Disclosure - Final Allocation of Purchase Price (Detail)</link:definition>
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<link:definition>1060 - Disclosure - Components of Intangible Assets and Their Estimated Useful Lives at Acquisition Date (Detail)</link:definition>
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<link:definition>1061 - Disclosure - Pro Forma Results Under Acquisition (Detail)</link:definition>
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<link:definition>1062 - Disclosure - Revenue - Additional Information (Detail)</link:definition>
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<link:definition>1063 - Disclosure - Disaggregated Revenue by Primary Geographical Market, Major Product Line and Timing of Revenue Recognition (Detail)</link:definition>
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<link:definition>1064 - Disclosure - Disaggregated Revenue by Primary Geographical Market, Major Product Line and Timing of Revenue Recognition (Parenthetical) (Detail)</link:definition>
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<link:definition>1065 - Disclosure - Composition of Inventories, Net (Detail)</link:definition>
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<link:definition>1066 - Disclosure - Inventories - Additional Information (Detail)</link:definition>
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<link:definition>1067 - Disclosure - Property Plant and Equipment, Net (Detail)</link:definition>
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<link:definition>1068 - Disclosure - Property, Plant and Equipment - Additional Information (Detail)</link:definition>
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<link:definition>1069 - Disclosure - Financial Instruments - Additional Information (Detail)</link:definition>
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<link:definition>1070 - Disclosure - Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail)</link:definition>
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<link:definition>1071 - Disclosure - Schedule of Reported Financial Assets and Liabilities (Detail)</link:definition>
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<link:definition>1072 - Disclosure - Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Detail)</link:definition>
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<link:definition>1073 - Disclosure - Schedule of Changes in Fair Value of Level 3 Contingent Consideration (Parenthetical) (Detail)</link:definition>
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<link:definition>1074 - Disclosure - Quantitative Information Associated With Fair Value Measurement of Level 3 Financial Instrument (Detail)</link:definition>
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<link:definition>1075 - Disclosure - Schedule of Carrying Amounts and Fair Values of Financial Instruments (Detail)</link:definition>
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<link:roleType roleURI="http://wwww.teradyne.com/role/ScheduleOfAvailableForSaleMarketableSecuritiesDetail" id="ScheduleOfAvailableForSaleMarketableSecuritiesDetail">
<link:definition>1076 - Disclosure - Schedule of Available for Sale Marketable Securities (Detail)</link:definition>
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<link:definition>1077 - Disclosure - Schedule of Reported Available for Sale Marketable Securities (Detail)</link:definition>
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<link:roleType roleURI="http://wwww.teradyne.com/role/ContractualMaturitiesOfInvestmentsInDebtSecuritiesHeldDetail" id="ContractualMaturitiesOfInvestmentsInDebtSecuritiesHeldDetail">
<link:definition>1078 - Disclosure - Contractual Maturities of Investments in Debt Securities Held (Detail)</link:definition>
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<link:roleType roleURI="http://wwww.teradyne.com/role/ScheduleOfNotionalAmountOfDerivativesDetail" id="ScheduleOfNotionalAmountOfDerivativesDetail">
<link:definition>1079 - Disclosure - Schedule of Notional Amount of Derivatives (Detail)</link:definition>
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<link:roleType roleURI="http://wwww.teradyne.com/role/ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionAtFairValueDetail" id="ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionAtFairValueDetail">
<link:definition>1080 - Disclosure - Schedule of Derivative Instruments in Statement of Financial Position at Fair Value (Detail)</link:definition>
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<link:definition>1081 - Disclosure - Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Detail)</link:definition>
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<link:definition>1082 - Disclosure - Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Parenthetical) (Detail)</link:definition>
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<link:roleType roleURI="http://wwww.teradyne.com/role/LeasesAdditionalInformationDetail" id="LeasesAdditionalInformationDetail">
<link:definition>1083 - Disclosure - Leases - Additional Information (Detail)</link:definition>
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<link:definition>1084 - Disclosure - Supplemental Cash Flow Information Related to Leases (Detail)</link:definition>
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<link:roleType roleURI="http://wwww.teradyne.com/role/ScheduleOfOperatingLeaseMaturityDetail" id="ScheduleOfOperatingLeaseMaturityDetail">
<link:definition>1085 - Disclosure - Schedule of Operating Lease, Maturity (Detail)</link:definition>
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<link:definition>1086 - Disclosure - Debt - Additional Information (Detail)</link:definition>
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<link:roleType roleURI="http://wwww.teradyne.com/role/ComponentsOfConvertibleSeniorNotesDetail" id="ComponentsOfConvertibleSeniorNotesDetail">
<link:definition>1087 - Disclosure - Components of Convertible Senior Notes (Detail)</link:definition>
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<link:definition>1088 - Disclosure - Interest Expense on Convertible Senior Notes (Detail)</link:definition>
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<link:definition>1089 - Disclosure - Changes in Accumulated Other Comprehensive (Loss) Income (Detail)</link:definition>
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<link:definition>1090 - Disclosure - Changes in Accumulated Other Comprehensive (Loss) Income (Parenthetical) (Detail)</link:definition>
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<link:definition>1091 - Disclosure - Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations (Detail)</link:definition>
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<link:definition>1092 - Disclosure - Reclassifications Out of Accumulated Other Comprehensive Income to Statements of Operations (Parenthetical) (Detail)</link:definition>
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<link:roleType roleURI="http://wwww.teradyne.com/role/GoodwillAndIntangibleAssetsAdditionalInformationDetail" id="GoodwillAndIntangibleAssetsAdditionalInformationDetail">
<link:definition>1093 - Disclosure - Goodwill and Intangible Assets - Additional Information (Detail)</link:definition>
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<link:definition>1094 - Disclosure - Changes in Carrying Amount of Goodwill by Segment (Detail)</link:definition>
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<link:roleType roleURI="http://wwww.teradyne.com/role/ScheduleOfAmortizableIntangibleAssetsDetail" id="ScheduleOfAmortizableIntangibleAssetsDetail">
<link:definition>1095 - Disclosure - Schedule of Amortizable Intangible Assets (Detail)</link:definition>
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<link:definition>1096 - Disclosure - Schedule of Amortizable Intangible Assets (Parenthetical) (Detail)</link:definition>
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<link:definition>1097 - Disclosure - Schedule of Estimated Intangible Asset Amortization Expense (Detail)</link:definition>
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<link:definition>1098 - Disclosure - Commitments and Contingencies - Additional Information (Detail)</link:definition>
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<link:definition>1099 - Disclosure - Computation of Basic and Diluted Net Income Per Common Share (Detail)</link:definition>
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<link:definition>1100 - Disclosure - Computation of Basic and Diluted Net Income Per Common Share (Parenthetical) (Detail)</link:definition>
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<link:definition>1101 - Disclosure - Net Income Per Common Share - Additional Information (Detail)</link:definition>
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<link:definition>1102 - Disclosure - Restructuring and Other - Additional Information (Detail)</link:definition>
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<link:roleType roleURI="http://wwww.teradyne.com/role/RetirementPlansAdditionalInformationDetail" id="RetirementPlansAdditionalInformationDetail">
<link:definition>1103 - Disclosure - Retirement Plans - Additional Information (Detail)</link:definition>
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<link:definition>1104 - Disclosure - Schedule of Defined Benefit Pension and Postretirement Benefit Plan Assets and Obligation (Detail)</link:definition>
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<link:definition>1105 - Disclosure - Schedule of Amounts Recorded within Statements of Financial Position (Detail)</link:definition>
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<link:definition>1106 - Disclosure - Schedule of Amounts Recognized in Accumulated Other Comprehensive Income (Detail)</link:definition>
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<link:definition>1107 - Disclosure - Schedule of Pension Plans with Accumulated Benefit Obligation and Projected Benefit Obligation in Excess of Plan Assets (Detail)</link:definition>
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<link:definition>1108 - Disclosure - Schedule of Net Periodic Pension and Postretirement (income) Cost (Detail)</link:definition>
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<link:definition>1109 - Disclosure - Schedule of Weighted Average - Assumptions to Determine Net Periodic Pension Cost (Detail)</link:definition>
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<link:definition>1110 - Disclosure - Schedule of Weighted Average Assumptions to Determine Pension Obligations (Detail)</link:definition>
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<link:definition>1111 - Disclosure - Schedule of Weighted Average Pension Assets Allocations by Category (Detail)</link:definition>
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<link:definition>1112 - Disclosure - Schedule of Target Assets Allocation (Detail)</link:definition>
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<link:definition>1113 - Disclosure - Schedule of Fair Value of Pensions Plan Assets by Asset Category (Detail)</link:definition>
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