Entry 1 sense Webster, 1913 Epispadias · Ep·i·spa·di·as · IPA /ˌɛp.ɪˈspeɪ.di.əs/ 01 n. A deformity in which the urethra opens upon the top of the penis, instead of at its extremity. 1. A deformity in which the urethra opens upon the top of the penis, instead of at its extremity.(Med.)