/ Dictionary / Index M masseter: Meaning and Definition of Find definitions for: mas•se•ter Pronunciation: (ma-sē'tur), [key] — n. Anat. a short, thick, masticatory muscle, the action of which assists in closing the jaws by raising the mandible or lower jaw. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: masseter (Thesaurus) Massenet masseur Related Content Daily Word Quiz: arid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language