/ Dictionary / Index P Pius I: Meaning and Definition of Find definitions for: Pi•us I Pronunciation: (pī'us), [key] — Saint, pope a.d.140–155?. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Piura Pius II 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