/ Dictionary / Index M mes-: Meaning and Definition of Find definitions for: mes- Pronunciation: [key] var. ofbefore vowels: mesencephalon. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mes- (Thesaurus) Meryl mesa Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language