/ Dictionary / Index J jack-up: Meaning and Definition of Find definitions for: jack-up Pronunciation: ( jak'up"), [key] — n. Informal. an increase or rise: a recent jack-up in prices. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: jack-up (Thesaurus) jack truss jack-up rig Related Content Daily Word Quiz: blithesome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language