The male genital organ of higher vertebrates, carrying the duct for the transfer of sperm during copulation. The doctor explained the anatomy of the penis during the health class.
An organ in certain invertebrates that is analogous to the male genital organ of vertebrates. The biologist studied the reproductive system of the snail, noting the structure of its penis.
A foolish or contemptible person (slang, derogatory). Stop acting like a total penis.