/ Dictionary / Index M multiplet: Meaning and Definition of Find definitions for: mul•ti•plet Pronunciation: (mul'tu-plet", -plit), [key] — n. Physics. a group of several related spectral lines, usually of nearly the same wavelengths. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. multiple star multiple-unit car Related Content Daily Word Quiz: quandary Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language