Defn: A quantity consisting of three terms, connected by the sign + or -; as, x + y + z, or ax + 2b - c2.
TRINOMIAL
Tri*no"mi*al, a. (Math.)
Defn: Consisting of three terms; of or pertaining to trinomials; as, a trinomial root.
TRINOMINAL Tri*nom"i*nal, n. & a. Etym: [Pref. tri- + L. nomen, nominis, name: cf. L. trinominis three-named.] (Math.)
Defn: Trinomial.
TRINUCLEUS
Tri*nu"cle*us, n. Etym: [Pref. tri- + nucleus.] (Paleon.)
Defn: A genus of Lower Silurian trilobites in which the glabella and cheeks form three rounded elevations on the head.
TRIO
Tri"o, n. Etym: [It., fr. L. tres, tria, three: cf. F. trio, from the
Italian. See Three.]
1. Three, considered collectively; three in company or acting together; a set of three; three united. The trio were well accustomed to act together, and were linked to each other by ties of mutual interest. Dickens.
2. (Mus.) (a) A composition for three parts or three instruments. (b) The secondary, or episodical, movement of a minuet or scherzo, as in a sonata or symphony, or of a march, or of various dance forms; — not limited to three parts or instruments.