As mentioned above the abbreviation WC stands for water closet. This is a toilet that employs water to flush waste down the drainage to a separate septic tank for later disposal and is mostly located indoors.In British English, bathroom is a common term but is typically reserved for private rooms primarily used for bathing; a room without a bathtub or shower is more often known as a WC, an abbreviation for water closet, or loo. ... Larger houses often have a secondary room with a toilet and sink for use by guests.