toilet room

noun2

1. •
   A room in which to use a toilet: a lavatory.

   • The other apartments are for toilet rooms for both sexes, on first and second floors. — 1854
2. •
   (historical) A room in which to perform one's toilet, including dressing and grooming, particularly before execution.

   • We first enter a set of apartments, that are fitted up as toilette-rooms for the ladies. — 1800