/ Dictionary / Index M MHz: Meaning and Definition of Find definitions for: MHz Pronunciation: [key] megahertz. mHz Pronunciation: [key] millihertz. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mhz (Thesaurus) M.H.W. mi Related Content Daily Word Quiz: arid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language