The Collaborative International Dictionary of English v.0.48:
Penis \Pe"nis\ (p[=e]"n[i^]s), n. [L.] (Anat.) The erectile external sexual organ of males, used in copulation, and in mammals, also for urination. [1913 Webster +PJC]WordNet (r) 3.0 (2006):
penis n 1: the male organ of copulation (`member' is a euphemism) [syn: penis, phallus, member]