/ Dictionary / Index M Mistassini: Meaning and Definition of Find definitions for: Mis•tas•si•ni Pronunciation: (mis"tu-sē'nē), [key] — n. a lake in E Canada, in Quebec province. 840 sq. mi. (2176 sq. km). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mistaken mistbow 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