Sink \Sink\, n. 1. A drain to carry off filthy water; a jakes. 2. A shallow box or vessel of wood, stone, iron, or other material, connected with a drain, and used for receiving filthy water, etc., as in a kitchen. 3. A hole or low place in land or rock, where waters sink and are lost; -- called also {sink hole}. [U. S.] {Sink hole}. (a) The opening to a sink drain. (b) A cesspool. (c) Same as {Sink}, n., 3.