emergency room, ER - a room in a hospital or clinic staffed and equipped to provide emergency care to persons requiring immediate medical treatment

hospital, infirmary - a health facility where patients receive treatment

operating room, operating theater, operating theatre, OR, surgery - a room in a hospital equipped for the performance of surgical operations; "great care is taken to keep the operating rooms aseptic"

recovery room - a hospital room for the care of patients immediately after surgery

room - an area within a building enclosed by walls and floor and ceiling; "the rooms were very small but they had a nice view"