Wiktionary
boys' room
n. A restroom for boys.
Usage examples of "boys' room".
It was two hours later that she came to the boys' room and awakened them, saying the front-door bell had rung.
As soon as they reached home, Joe carried the invention to the boys' room and hid it.
Frank dashed back to the boys' room and told his brother the latest news.
Back in the boys' room, they fell on the mattress and roared until they wept, and couldn't say what was so funny.