middle voice

Wiktionary

1. n. grammar The form in which the subject of a verb performs some action upon itself.

GNU Webster's 1913

1. adj. (Gram.) See under Voice.
2. n. (Gram.) that form of verb by which its subject is represented as both the agent, or doer, and the object of the action, that is, as performing some act to or upon himself, or for his own advantage.