The Collaborative International Dictionary
Equipollency
Equipollence \E`qui*pol"lence\, Equipollency \E`qui*pol"len*cy\, n. [Cf. F. ['e]quipollence. See Equipollent.]
Equality of power, force, signification, or application.
--Boyle.(Logic) Sameness of signification of two or more propositions which differ in language.
Wiktionary
equipollency
n. (alternative form of equipollence English)