/ Dictionary / Index P Pius IX: Meaning and Definition of Find definitions for: Pius IX Pronunciation: [key] (Giovanni Maria Mastai-Ferretti) 1792–1878, Italian ecclesiastic: pope 1846–78. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Pius VIII Pius X Related Content Daily Word Quiz: pugilist Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language