Logic. (of propositions, propositional forms, etc.) logically equivalent in any of various specified ways.
–noun
3.
an equivalent.
Origin: 1375–1425; late ME < L aequipollent- (s. of aequipollēns) of equal value, equiv. to aequi-equi-+ pollent- (s. of pollēns) able, prp. of pollēre to be strong