/ Dictionary / Index S step function: Meaning and Definition of Find definitions for: step' func"tion Pronunciation: [key] — Math. Math. a function that is constant on each of a finite set of subintervals of its domain, the union of the subintervals being the domain. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. stepfather Stephanie Related Content Daily Word Quiz: sinister Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language