define ratchet
A socket wrench is a type of wrench or spanner that has a socket attached at one end, usually used to turn a fastener. The most prevalent form is the ratcheting socket wrench, often called a ratchet. A ratchet is a hand tool in which a metal handle is attached to a ratcheting mechanism, which attaches to a socket, which in turn fits onto a type of bolt or nut. Pulled or pushed in one direction, the ratchet loosens or tightens the bolt or nut attached to the socket. Turned the other direction, the ratchet does not turn the socket but allows the ratchet handle to be re-positioned for another turn while staying attached to the bolt or nut.