/ Dictionary / Index S spectral series: Meaning and Definition of Find definitions for: spec'tral se'ries Pronunciation: [key] — Physics. Physics. a series of lines in the spectrum of light emitted by excited atoms of an element, each line being related to the others in the series by a simple numerical equation and identified with a particular energy level of an atom of the element. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. spectral line spectral type Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language