/ Dictionary / Index M mortarboard: Meaning and Definition of Find definitions for: mor•tar•board Pronunciation: (môr'tur-bôrd", -bōrd"), [key] — n. a board, usually square, used by masons to hold mortar. Also calleda cap with a close-fitting crown surmounted by a stiff, flat, square piece from which a tassel hangs, worn as part of academic costume. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mortarboard (Thesaurus) mortar mortar ketch Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language