trinomial

Consisting of three names or terms, as a taxonomic designation.

Consisting of three terms.

A three-part taxonomic designation indicating genus, species, and subspecies or variety, such as Brassica oleracea botrytis, the cauliflower.

An algebraic expression consisting of three terms connected by plus or minus signs, such as x² + 4x -3.

In zoology and botany:

Consisting of three terms, as the technical name of a subspecies; trionymal: thus, the name Certhia familiaris americana is trinomial. See binomial, polynomial.

Using or admitting trinomial or trionymal names in certain cases: as, the trinomial system of nomenclature. Also trinominal.

In algebra, consisting of three terms connected by either of the signs + and—: thus, a + b + c, or x—2 xy + y is a trinomial quantity.

A technical name consisting of three words, of which the first is the name of the genus, the second that of the species, and the third that of a geographical race, subspecies, or variety; a trionym.

In algebra, a trinomial expression. See I., 2.