"divided in two parts," 1650s, from Latin bifarius "twofold, double," probably originally "that which can be expressed in two ways" [Klein], from bi- "two" (see bi-) + fari "to speak, say" (from PIE root *bha- (2) "to speak, tell, say"). Related: Bifariously.
bidirectional
Biedermeier
biennial
biennium
bier
bifarious
biff
bifid
bifocal
bifocals
bifold