equivalence [ih-kwiv -uh -luh ns or for 3 , ee-kwuh -vey -luh ns] noun Also equivalency (for defs 1, 2) . the state or fact of being equivalent; equality in value, force, significance, etc.

an instance of this; an equivalent.

Chemistry . the quality of having equal valence.

Logic , Mathematics . Also called material implication . the relation between two propositions such that the second is not false when the first is true. Also called material equivalence. the relation between two propositions such that they are either both true or both false. the relation between two propositions such that each logically implies the other. Show More

adjective (of a logical or mathematical relationship) reflexive, symmetrical, and transitive.

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Origin of equivalence 1535–45; <

Middle French <

Medieval Latin aequivalentia, equivalent to

Latin aequivalent- equivalent +

-ia -ia ; see

-ence Related forms non·e·quiv·a·lence , noun Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for material-equivalence noun the state of being equivalent or interchangeable

maths logic the relationship between two statements, each of which implies the other Also called: biconditional the binary truth-function that takes the value true when both component sentences are true or when both are false, corresponding to English if and only if . Symbol: ≡ or ↔, as in –(p ∧ q ) ≡ – p ∨ – q Show More

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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Word Origin and History for material-equivalence n. 1540s, from French équivalence , from Medieval Latin aequivalentia , from aequivalentem (see equivalent ). Related: Equivalency (1530s).

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Online Etymology Dictionary, © 2010 Douglas Harper