trinomial adj
1 (Maths) consisting of or relating to three terms
2 (Biology) denoting or relating to the three-part name of an organism that incorporates its genus, species, and subspecies n
3 (Maths) a polynomial consisting of three terms, such as ax² + bx + c
4 (Biology) the third word in the trinomial name of an organism, which distinguishes between subspecies
(C18: tri- + -nomial on the model of binomial)
♦
trinomially adv