/ Dictionary / Index J jam-up: Meaning and Definition of Find definitions for: jam-up Pronunciation: ( jam'up"), [key] — n. a stoppage or slowing of motion, work, or the like, due to obstruction, overloading, malfunction, or inefficiency; jam: Your letters didn't go out yesterday because there was a jam-up in the mail room. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Jamshid Jan Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language