/ Dictionary / Index B band spectrum: Meaning and Definition of Find definitions for: band' spec"trum Pronunciation: [key] — Physics. Physics. an optical spectrum consisting of groups of closely spaced spectral lines, characteristic of molecules. Cf. continuous spectrum, line spectrum. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. bandsman bandstand Related Content Daily Word Quiz: blanch Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language