A chair is a piece of furniture. It is used for sitting on. They usually have four legs to support the weight. Some types of chairs, such as the barstool, have only one leg in the center. Those chairs are usually able to spin.[source?] Sometimes chairs have armrests. These chairs may be called armchairs. There are many types of chairs such as Windsor chairs and rocking chairs. There is another type of chair called a sofa or settee. This is often used for comfort and can fit more than one person on it.