·adj Consisting of three terms; of or pertaining to trinomials; as, a trinomial root.
II. Trinomial ·noun A quantity consisting of three terms, connected by the sign + or -; as, x + y + z, or ax + 2b - c2.
III. Trinomial ·add. ·adj Consisting of, or involving the use of, three terms; as, a trinomial systematic name specifying the genus, species, and variety.