/ Dictionary / Index E epididymis: Meaning and Definition of Find definitions for: ep•i•did•y•mis Pronunciation: (ep"i-did'u-mis), [key] — pl. -di•dym•i•des an elongated organ on the posterior surface of a testis that constitutes the convoluted beginning of the vas deferens. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: epididymis (Thesaurus) epidiascope epidiorite Related Content Daily Word Quiz: portent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language