water closet

noun
  1. A small room or compartment containing a toilet and typically a washbasin. noun
    The hotel room includes a water closet with modern amenities.
    Please excuse me, I need to use the water closet.
  2. A toilet, especially one that is part of a plumbing system and uses water to flush waste away. noun
    The water closet was invented in the late 19th century.
    He installed a new water closet in the bathroom to improve the plumbing.