/ Dictionary / Index M mtn: Meaning and Definition of Find definitions for: mtn Pronunciation: [key] mountain. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. MTI MTO Related Content Daily Word Quiz: dissonant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language