/ Dictionary / Index E endocardium: Meaning and Definition of Find definitions for: en•do•car•di•um Pronunciation: (en"dō-kär'dē-um), [key] — pl. -di•a the serous membrane that lines the cavities of the heart. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: endocardium (Thesaurus) endocarditis endocarp 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