W.C = water closet, another term for lavatory or wash room. It is used by the Europeans. Many Americans do not even know what it means. Toilet = Used by continental Europeans to refer to a washroom. The English and Americans use it to mean the actual piece of equipment you use. We try to avoid using it to refer to the room. Washroom = a polite term for the lavatory. Used to refer to any kind of public lavatory or toilet. Closet = any small room you store things that you use a lot - espeically clothes. It has nothing to do with toilets.

They all mean the same thing and maybe you meant 'water closet'?