/ Dictionary / Index M mass spectrum: Meaning and Definition of Find definitions for: mass' spec'trum Pronunciation: [key] a spectrum of charged particles, arranged in order of mass or mass-to-charge ratios. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mass spectroscope mass transit Related Content Daily Word Quiz: exemplary Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language