Pronunciation: (trī-nō'mē-ul),[key] —adj. 1. Algebra.consisting of or pertaining to three terms.
2. Biol. a. pertaining to a scientific name comprising three terms, as of genus, species, and subspecies or variety.
b. characterized by the use of such names.
—n. 1. Algebra.an expression that is a sum or difference of three terms, as 3x + 2y + z or 3x3 + 2x2 + x. 2. Biol.a trinomial name, as Rosa gallica pumila.