POLYATOMIC

polyatomic

(adjective) of or relating to a molecule made up of more than two atoms

Source: WordNet® 3.1

Etymology

Adjective

polyatomic (comparative more polyatomic, superlative most polyatomic)

(chemistry) (of a molecule or ion) Consisting of three or more atoms.

Source: Wiktionary

Pol`y*a*tom"ic, a. Etym: [Poly- + atomic.] (Chem.) (a) Having more than one atom in the molecule; consisting of several atoms. (b) Having a valence greater than one. [Obs.]

Source: Webster’s Unabridged Dictionary 1913 Edition