/ Dictionary / Index E endothelioma: Meaning and Definition of Find definitions for: en•do•the•li•o•ma Pronunciation: (en"dō-thē"lē-ō'mu), [key] — pl. -mas, -ma•ta a tumor originating from the endothelium. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. endothelioid endothelium Related Content Daily Word Quiz: nonchalant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language