/ Dictionary / Index A Antoninus Pius: Meaning and Definition of Find definitions for: Antoni'nus Pi'us Pronunciation: (pī'us), [key] a.d. 86–161, emperor of Rome 138–161. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Antoninus Antonioni Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language