An anchor is a device, usually made of metal, that connects a boat to a body of water to prevent it from drifting due to wind or current. The word comes from the Latin encora, which itself comes from the Greek ankura.

Anchors can be temporary or permanent. Permanent anchors are used in anchoring with little movement. Professional services are often required to move or maintain them. The vessel has one or more temporary anchors, which may have different designs and weights.

A sea anchor is a tapered hole that does not contact the seabed and is used to control a drifting boat.