A chair is a kind of furniture whose raised surface is supported by legs and is usually used for a person to sit down. Chairs are most often supported by four feet and have a back. However, chairs can have three legs or can have different shapes. Chairs are made of a variety of materials, from wood to metal to synthetic materials (such as plastics), and can be filled or decorated with various colors and fabrics on the seats (such as some dining chairs). Or the whole chair. Chairs are used in many rooms of the family (for example, in living rooms, dining rooms and study rooms), schools and offices (with desks), and various other workplaces.

A chair without a back or armrest is a stool, or a barstool when raised. Chairs with arms are armchairs with cushions, reclining movements and foldable footrests and reclining chairs. The seat permanently fixed in a train or theater is a seat, or an aircraft seat in an airplane; when riding, it is a saddle and bicycle saddle, suitable for cars, car seats or baby car seats. Wheelchair with wheels, swing from above. The cushioned chairs for many people are sofa, sofa, bench or "double sofa". Or, if there is no upholstery, a bench. A single footstool, usually a padded chair, is called a footstool, bench, or bench.