/ Dictionary / Index J jumping mouse: Meaning and Definition of Find definitions for: jump'ing mouse" Pronunciation: [key] any of several primitive, mouselike rodents of the family Zapodidae, having long hind legs, common in the woodlands of Europe, Asia, and North America. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. jumping jack jumping-off place Related Content Daily Word Quiz: dissonant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language