British restroom (3)
I believe the answer is:
loo
'british restroom' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for loo that I've seen before include "Toilet (informal)" , "Card game; the 'smallest room'" , "Little boys' room" , "Lavatory - old card game" , "In which one goes" .)