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