From Longman Dictionary of Contemporary Englishchanging roomˈchanging room noun [countable] British English DSTBBa room where people change their clothes when they play sports, go swimming etc SYN locker room American English
Examples from the Corpus
changing room• And Marcus came to be walking between them to a partitioned corner of the changing room.• Marie asks one of the old women if she can use the changing room, and she shows her where it is. 