[trahy-noh-mee-uh l]


Algebra. consisting of or pertaining to three terms.
  1. pertaining to a scientific name comprising three terms, as of genus, species, and subspecies or variety.
  2. characterized by the use of such names.


Algebra. an expression that is a sum or difference of three terms, as 3x + 2y + z or 3x3 + 2x2 + x.
Biology. a trinomial name, as Rosa gallica pumila.

Origin of trinomial

First recorded in 1665–75; tri- + (bi)nomial
Related formstri·no·mi·al·ly, adverb Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for trinomial

Historical Examples of trinomial

British Dictionary definitions for trinomial



maths consisting of or relating to three terms
biology denoting or relating to the three-part name of an organism that incorporates its genus, species, and subspecies


maths a polynomial consisting of three terms, such as ax ² + bx + c
biology the third word in the trinomial name of an organism, which distinguishes between subspecies
Derived Formstrinomially, adverb

Word Origin for trinomial

C18: tri- + -nomial on the model of binomial
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for trinomial

1670s, from tri- + second element from binomial.

Online Etymology Dictionary, © 2010 Douglas Harper

trinomial in Science



A mathematical expression that is the sum of three monomials, such as ax2 + bx - c.
A taxonomic designation indicating genus, species, and subspecies or variety, as in Brassica oleracea botrytis, the cauliflower.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.