"Residential care facility," defined as a dwelling unit or dwelling units within a building providing twenty-four-hour supervised room, board and care in a residential setting to residents thereof whose status limits their ability to live independently, and secondarily for training, rehabilitation and nonclinical services. A room or rooms may be regularly locked where a matter of owner policy, and occupancy is by a person, persons, or family as authorized by the operator. Residential care facilities shall not include a clinic, institution, hospital, nursing home, convalescent home, school, child day-care center, nursery school, dormitory, homeless residential facilities or other similar use. The term shall not be applied to owner-occupied premises with one or two roomers.