/ Dictionary / Index D diesel engine: Meaning and Definition of Find definitions for: die'sel en"gine Pronunciation: [key] a compression-ignition engine in which a spray of fuel, introduced into air compressed to a temperature of approximately 1000° F (538° C), ignites at a virtually constant pressure. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. diesel-electric diesel fuel Related Content Daily Word Quiz: belligerent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language