- a combining form meaning “twice,” “two,” used in the formation of compound words: bifacial; bifarious.
Origin of bi-1
- variant of bio-, especially before a vowel: biopsy.
sometimes before a vowel bin-
- two; having twobifocal
- occurring every two; lasting for twobiennial
- on both sides, surfaces, directions, etcbilateral
- occurring twice duringbiweekly
- denoting an organic compound containing two identical cyclic hydrocarbon systemsbiphenyl
- (rare in technical usage) indicating an acid salt of a dibasic acidsodium bicarbonate
- (not in technical usage) equivalent of di- 1 (def. 2a)
Word Origin for bi-
- a variant of bio-
Word Origin and History for bi-
word-forming element meaning "two, twice, double, doubly, once every two," etc., from Latin bi- "twice, double," from Old Latin dvi- (cognate with Sanskrit dvi-, Greek di-, Old English twi- "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).