/ Dictionary / Index T trigeminal: Meaning and Definition of Find definitions for: tri•gem•i•nal Pronunciation: (trī-jem'u-nl), [key] — Anat. Anat. —adj. of or pertaining to the trigeminal nerve. —n. Also called trigem&prim;inal nerve&prim;. either one of the fifth pair of cranial nerves, consisting of motor fibers that innervate the muscles of mastication, and of sensory fibers that conduct impulses from the head and face to the brain. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: trigeminal (Thesaurus) trigamy trigeminal neuralgia Related Content Daily Word Quiz: profiterole Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language