/ Dictionary / Index J jacking engine: Meaning and Definition of Find definitions for: jack'ing en"gine Pronunciation: [key] an engine for moving an idle reciprocating engine or turbine to permit inspection and repairs. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. jackie tar jack-in-the-box Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language