/ Dictionary / Index J jump discontinuity: Meaning and Definition of Find definitions for: jump' discontinu"ity Pronunciation: [key] — Math. Math. a discontinuity of a function at a point where the function has finite, but unequal, limits as the independent variable approaches the point from the left and from the right. Cf. jump (def. 60). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. jump dial jumped-up Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language