/ Dictionary / Index M megahertz: Meaning and Definition of Find definitions for: meg•a•hertz Pronunciation: (meg'u-hûrts"), [key] — pl. -hertz, -hertz•es. a unit of frequency, equal to one million cycles per second. Abbr.: MHz Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: megahertz (Thesaurus) megagametophyte megahit Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language