a basin for washing the hands (`wash-hand basin' is a British expression)
a bathroom sink that is permanently installed and connected to a water supply and drainpipe; where you can wash your hands and face; "he ran some water in the basin and splashed it on his face"
(American football) a play in which a defensive player is allowed to cross the line of scrimmage and then blocked off as the runner goes through the place the lineman vacated