/ Dictionary / Index L laser: Meaning and Definition of Find definitions for: la•ser Pronunciation: (lā'zur), [key] — n. Physics. a device that produces a nearly parallel, nearly monochromatic, and coherent beam of light by exciting atoms to a higher energy level and causing them to radiate their energy in phase. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: laser (Thesaurus) lase laser beam Related Content Daily Word Quiz: menagerie Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language