/ Dictionary / Index M major planet: Meaning and Definition of Find definitions for: ma'jor plan'et Pronunciation: [key] planet (def. 1a). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. major piece major premise Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language