/ Dictionary / Index P periodic function: Meaning and Definition of Find definitions for: per'i•od'ic func'tion Pronunciation: (pēr'ē-od'ik, pēr"-), [key] — Math. Math. a function of a real or complex variable that is periodic. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. periodic decimal periodicity Related Content Daily Word Quiz: belligerent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language