/ Dictionary / Index F Fidei Defensor*: Meaning and Definition of Find definitions for: Fi•de•i De•fen•sor Pronunciation: (fē'de-ē" de-fen'sōr Eng. fī'dē-ī" di-fen'sôr), [key] — Latin. Latin. Defender of the Faith: one of the titles of English sovereigns. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. fideicommissum fideism Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language