biplicity (n.)

word-forming element meaning "two, having two, twice, double, doubly, twofold, once every two," etc., from Latin bi- "twice, double," from Old Latin dvi- (cognate with Sanskrit dvi-, Greek di-, dis-, Old English twi-, German zwei- "twice, double"), from PIE root *dwo- "two."

Nativized from 16c. Occasionally bin- before vowels; this form originated in French, not Latin, and might be partly based on or influenced by Latin bini "twofold" (see binary). In chemical terms, it denotes two parts or equivalents of the substance referred to. Cognate with twi- and di- (1).

"state of being manifold or various," mid-15c., multiplicite, from Old French multiplicité or directly from Late Latin multiplicitas "manifoldness, multiplicity," from Latin multiplic-, stem of multiplex "many times as great in number" (see multiple). Related: Multiplicitous.