Quad room: a quad room is set up for four people to stay comfortably. This means the room will have two double beds. Some, however, may be set up dormitory-style with bunks or twins, so check with the property to make sure
Studio: this type of room has a studio bed, e.g. a couch that can be converted into a bed. Some studios come with additional beds. Others come with more space: a studio room can be like a fully-furnished apartment, meaning it will have a small kitchenette. Check with the hotel to learn more about their studio rooms.
Single room: these rooms are assigned to one person or a couple. It may have one or more beds, but the size of the bed depends on the hotel. Some single rooms have a twin bed, most will have a double, few will have a queen bed.