/ Dictionary / Index M mesial: Meaning and Definition of Find definitions for: me•si•al Pronunciation: (mē'zē-ul, -sē-, mez'ē-ul, mes'-), [key] — adj. medial. directed toward the sagittal plane or midline of the face, along the dental arch. Cf.(def. 3),(def. 2). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mesial (Thesaurus) meshy mesic Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language