backhouse

Etymology
From.

Noun

 * 1)  An outbuilding behind the main building, or an  attached to the rear of it; especially, a  or.
 * 2)  An outhouse: an outbuilding used as a lavatory.
 * 1)  An outhouse: an outbuilding used as a lavatory.

Synonyms

 * ; see also Thesaurus:bathroom