/ Dictionary / Index E endosymbiosis: Meaning and Definition of Find definitions for: en•do•sym•bi•o•sis Pronunciation: (en"dō-sim"bē-ō'sis, -bī-), [key] — n. Biol. symbiosis in which one symbiont lives within the body of the other. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. endosymbiont endothecium Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language