/ Dictionary / Index E episternum: Meaning and Definition of Find definitions for: ep•i•ster•num Pronunciation: (ep"u-stûr'num), [key] — pl. -na manubrium. the anterior portion of a pleuron. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. epistemology epistle Related Content Daily Word Quiz: cetacean Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language