1. (n.) An expression consisting of two terms connected by the sign plus (+) or minus (-); as, a + b, or 7 - 3.

2. (a.) Consisting of two terms; pertaining to binomials; as, a binomial root.

3. (a.) Having two names; -- used of the system by which every animal and plant receives two names, the one indicating the genus, the other the species, to which it belongs.

Linnaean biaxial bicameral bicuspid bifid biform binocular binominal bipartite biped bipetalous bipinnate bisexual bivalent classificatory nomenclatural onomastic orismological taxonomic terminological toponymic toponymous trinomial unibivalent