/ Dictionary / Index L light bulb: Meaning and Definition of Find definitions for: light' bulb" Pronunciation: [key] an electric light. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: lightbulb (Thesaurus) light bridge light chain Related Content Daily Word Quiz: lunar Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language