Definition of rat house in English:

rat house

noun

  • 1North American a large conical structure built from marsh vegetation and lived in by muskrats.

  • 2= rat firm (now historical).

  • 3Australian and NZ slang a psychiatric hospital.

Origin

Mid 19th century; earliest use found in The Spirit of the Times: a chronicle of the turf, agriculture, field sports, literature and the stage.