/ Dictionary / Index C Calixtus III: Meaning and Definition of Find definitions for: Calixtus III Pronunciation: [key] 1378–1458, Spanish ecclesiastic: pope 1455–58. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Calixtus II calk Related Content Daily Word Quiz: reiterate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language