/ Dictionary / Index M must-see: Meaning and Definition of Find definitions for: must-see Pronunciation: (must'sē'), [key] — n. Informal. something, as a remarkable sight or entertainment, that should be seen or attended: The new play is a must-see. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mustn't musty Related Content Daily Word Quiz: abominable Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language