/ Dictionary / Index G glow plug: Meaning and Definition of Find definitions for: glow' plug" Pronunciation: [key] — Auto., Mach. Auto.,Mach. a device for each cylinder of a diesel engine with a heating element to heat the incoming fuel and air so that combustion will take place more readily when the engine is cold. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. glow lamp glowworm Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language