m confuse between sink and wash basin

Sink means "go down below the surface of something, especially of a liquid; become submerged". wash basin mean "a basin, typically fixed to a wall or on a pedestal, used for washing one's hands and face".

The difference between Sink and Washbasin. When used as nouns, sink means a basin used for holding water for washing, whereas washbasin means a basin used for washing, particularly a permanently installed sink, fitted with a water supply and a drain, in which one may wash one's hands and face.