(1):
(a.) Consisting of two terms; pertaining to binomials; as, a binomial root.
(2):
(a.) Having two names; - used of the system by which every animal and plant receives two names, the one indicating the genus, the other the species, to which it belongs.
(3):
(n.) An expression consisting of two terms connected by the sign plus (+) or minus (-); as, a + b, or 7 - 3.