/ Dictionary / Index M millennialism: Meaning and Definition of Find definitions for: mil•len•ni•al•ism Pronunciation: (mi-len'ē-u-liz"um), [key] — n. a belief in the millennium. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Millennial Church millennium 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