a bathroom or lavatory sink that is permanently installed and connected to a water supply and drainpipe; where you wash your hands and face; "he ran some water in the basin and splashed it on his face"
(1) A room equipped with washing and often toilet facilities; a bathroom (2) A washbowl or basin, especially one permanently installed with running water (3) A flush toilet
A lavatory is the same as a toilet. the ladies' lavatory at the University of London. a public lavatory. = toilet. lavatories a toilet or the room a toilet is in