/ Dictionary / Index P Pius III: Meaning and Definition of Find definitions for: Pius III Pronunciation: [key] (Francesco Nanni Todeschini Piccolomini) 1439–1503, Italian ecclesiastic: pope 1503. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Pius II Pius IV Related Content Daily Word Quiz: eureka Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language