TRINO'MIAL, adjective [Latin tres and nomen.] In mathematics, a trinomial root, is a root consisting of three parts, connected by the signs + or -. Thus x+y+z, or a+b-c. TRINO'MIAL, noun A root of three terms or parts.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI