/ Dictionary / Index E ex officio: Meaning and Definition of Find definitions for: ex of•fi•ci•o Pronunciation: (eks' u-fish'ē-ō"), [key] by virtue of office or official position. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ex off. exogamy Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language