An Etymological Dictionary of Astronomy and Astrophysics

1a) An algebraic expression containing 2 terms, as x + y and 2x² - 3x. In other words, a → polynomial with 2 terms.

1b) Biology: A pair of Latin (or latinized) words forming a scientific name for organisms. The first word represents the genus, and the second the species.

2. Of, pertaining to, or consisting of a binomial.

See also: From L.L. binomi(us) “having two names,” + → -al, → nominal.