/ Dictionary / Index M MX: Meaning and Definition of Find definitions for: MX Pronunciation: [key] missile experimental: a ten-warhead U.S. intercontinental ballistic missile. Mx Pronunciation: [key] maxwell; maxwells. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mx (Thesaurus) M.W.T. my Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language