1. (n.) A quantity consisting of three terms, connected by the sign + or -; as, x + y + z, or ax + 2b - c2.

2. (a.) Consisting of three terms; of or pertaining to trinomials; as, a trinomial root.

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