/ Dictionary / Index M mountain bike: Meaning and Definition of Find definitions for: moun'tain bike" Pronunciation: [key] a bicycle designed for off-road use, typically having a smaller and sturdier frame and smaller and wider tires than a standard bicycle. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mountain beaver mountain bluebird Related Content Daily Word Quiz: maritime Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language