A dorm room was a room in a dormitory which housed its occupants. Starfleet Academy and Starfleet Training Command both had dorm rooms.
In 2154, Trip Tucker commented that Enterprise NX-01's decon chamber reminded him of his dorm room at Starfleet Training Command. (ENT: "Observer Effect")
As a cadet, Harry Kim requested baryon sweeps of his Academy dorm room due to the sloppiness of fellow cadet Lyndsay Ballard. When she asked him years later whether his tidiness explained his requests, he blamed her for being a slob. (VOY: "Ashes to Ashes")