/ Dictionary / Index M mas.: Meaning and Definition of Find definitions for: mas. Pronunciation: [key] masculine. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mas (Thesaurus) marzipan masa 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