/ Dictionary / Index I Isabella I: Meaning and Definition of Find definitions for: Isabella I Pronunciation: [key] — (“the Catholic”), 1451–1504, wife of Ferdinand V: queen of Castile 1474–1504; joint ruler of Aragon 1479–1504. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Isabella* isabnormal Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language