From Longman Dictionary of Contemporary Englishdressing roomˈdressing room noun [countable] 1 APTa room where an actor or performer can get ready before going on stage, appearing on television etc2 American English a room or area in a store where you can try on clothes SYN changing room British English3 DHHa small room next to a bedroom in some houses where you can get dressed
Examples from the Corpus
dressing room• Julie Rose would be there and would return the yellow shoes I'd left in a dressing room two weeks ago.• Bivins listened to their music in his dressing room and a few months later signed them up.• He spent the interval just sitting in his dressing room, gathering his strength for the next act.• So why was he all smiles in his dressing room after the fight?• He went back into the dressing room, took a shot and came back to play. 