equivalencen.[Cf. F. quivalence, LL. aequivalentia.]1. The condition of being equivalent or equal; equality of worth, value, signification, or force; as, an equivalence of definitions.()2. Equal power or force; equivalent amount.()3. (Chem.) 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. See Valence.()v. t. To be equivalent or equal to; to counterbalance.(Sir T. Browne.)