noun
(uncountable) The condition of being equivalent or essentially equal.
(countable, mathematics) An equivalence relation; ≡; ~
(uncountable, logic) The relationship between two propositions that are either both true or both false.
(chemistry) The quantity of the combining power of an atom, expressed in hydrogen units; the number of hydrogen atoms can combine with, or be exchanged for; valency.
(mathematics) A Boolean operation that is TRUE when both input variables are TRUE or both input variables are FALSE, but otherwise FALSE; the XNOR function.
(geometry) A number in intersection theory. A positive-dimensional variety sometimes behaves formally as if it were a finite number of points; this number is its equivalence.
(translation studies) The degree to which a term or text in one language is semantically similar to its translated counterpart.
verb
(transitive) To be equivalent or equal to; to counterbalance.