Wiktionary
smallest room
n. 1 (label en euphemistic) toilet, lavatory or loo 2 (label en euphemistic) bathroom (qualifier: US)
Usage examples of "smallest room".
And then he was once again facing Kessell, this time in the smallest room of the structure.
This burst of activity dwindled to rest in the smallest room he could find, a fourth-floor chamber which, but for its window, might have passed for a closet.
It was the smallest room in the inn, to be sure, up under the eaves in the back, and the meal came in the middle of along night of playing and juggling, but it was still a bed beneath a roof.
I could feel them, both of them in the smallest room to the left, our guest room.
He was seated upon the throne in our home's smallest room, with the newspaper in his lap.