Penis

In many animals, a penis (/ˈpiːnɪs/; pl.: penises or penes) is the main male sexual organ used to inseminate females (or hermaphrodites) during copulation. Such organs occur in both vertebrates and invertebrates, but males do not bear a penis in every animal species.

The term penis applies to many intromittent organs, but not to all. As an example, the intromittent organ of most Cephalopoda is the hectocotylus, a specialized arm, and male spiders use their pedipalps. Even within the Vertebrata, there are morphological variants with specific terminology, such as hemipenes.