/ Dictionary / Index C costard: Meaning and Definition of Find definitions for: cos•tard Pronunciation: (kos'turd, kô'sturd), [key] — n. a large English variety of apple. the head. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. costar Costa Rica Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language