/ Dictionary / Index P principal value: Meaning and Definition of Find definitions for: prin'cipal val'ue Pronunciation: [key] — Math. Math. a value selected at a point in the domain of a multiple-valued function, chosen so that the function has a single value at the point. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. principal sum principate Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language