/ Dictionary / Index P proper function: Meaning and Definition of Find definitions for: prop'er func'tion Pronunciation: [key] — Math. Math. eigenfunction. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. proper fraction proper motion Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language