/ Dictionary / Index H Heaviside unit function: Meaning and Definition of Find definitions for: Heav'iside u'nit func"tion Pronunciation: [key] — Math. Math. the function that is zero for any number less than zero and that is 1 for any number greater than or equal to zero. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Heaviside layer heavy Related Content Daily Word Quiz: abstain Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language