little girls' room

Meanings

1. Synonym of ladies' room: a public lavatory intended for use by women.
2. Used other than figuratively or idiomatically: A room belonging to or used by little girls, particularly their bedroom.

Etymology

Originally from the need to find public lavatories for children, possibly by analogy with the somewhat earlier-attested little boys' room, but already in broader euphemistic use by its first known appearance in John O'Hara's BUtterfield 8.