/ Dictionary / Index E EO: Meaning and Definition of Find definitions for: EO Pronunciation: [key] executive order. eo- Pronunciation: [key] a combining form meaning “early,” “primeval,” used in the formation of compound words: Eocene; eohippus. e.o. Pronunciation: [key] ex officio. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. enzymolysis Eoanthropus* Related Content Daily Word Quiz: crockery Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language