equivalence

American  

[ih-kwiv-uh-luhns, ee-kwuh-vey-luhns] / ɪˈkwɪv ə ləns, ˌi kwəˈveɪ ləns /

noun

1. the state or fact of being equivalent; equality in value, force, significance, etc.

2. an instance of this; an equivalent.

3. Chemistry. the quality of having equal valence.

4. Logic, Mathematics.

   1. Also called material implication.  the relation between two propositions such that the second is not false when the first is true.

   2. Also called material equivalence.  the relation between two propositions such that they are either both true or both false.

   3. the relation between two propositions such that each logically implies the other.

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adjective

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

equivalence British  

/ ɪˈkwɪvələns /

noun

1. the state of being equivalent or interchangeable

2. maths logic

   1. the relationship between two statements, each of which implies the other

   2. 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

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Other Word Forms

• nonequivalence
  noun

Etymology

Origin of equivalence

1535–45; < Middle French < Medieval Latin aequivalentia, equivalent to Latin aequivalent- equivalent + -ia -ia; see -ence

Explanation

If you were having trouble choosing between chocolate cake and an ice cream sundae because you love both equally, you might say these two treats have an equivalence. The noun equivalence describes the state of being equal, and it can be used any time things are basically interchangeable. If you came down with a stomach bug and there were three different medicines your doctor could prescribe — any one of them being likely to cure you — they would have an equivalence. In math, the word equivalence comes up a lot, and it's always represented by an equal sign.

Example Sentences

This functional equivalence is illustrated in the accompanying chart.

From MarketWatch • Feb. 26, 2026

Dr Bączyk-Bell said the process had been a "facetious charade" and it was a "false equivalence" to talk about hurt caused to those who had been theologically opposed to the idea of marriage equality.

From BBC • Feb. 12, 2026

"More problematically, matching adversaries' tone risks creating equivalence in audiences' minds between democratic institutions and disinformation actors."

From Barron's • Jan. 23, 2026

This much is grounds for legitimate moral equivalence.

From The Wall Street Journal • Oct. 27, 2025

In fact, the equivalence between gravitational forces and the forces we would feel in an accelerating spaceship is a major feature of Einstein’s later general theory of relativity.

From "Cosmos" by Carl Sagan