Chair

A chair is a piece of furniture designed for a single person to sit on. In its typical form it consists of a seat (a flat upper surface), supporting legs, and usually a backrest to support the person's back. Many chairs also have armrests.

Chairs are made from various materials: wood, metal, plastic, rattan, or combinations of these. The seat is sometimes covered with cloth or leather and padded for comfort. The standard height of the seat is approximately 40–50 centimetres, so that the sitter's feet reach the ground.

Parts of a chair

The main parts are the seat, which bears the person's weight; the legs, usually four but sometimes a single central pedestal; the backrest, which supports the spine; and the armrests. Office chairs often have casters and a mechanism to adjust the height.

Types

There are many types suited to different uses: dining chairs, office swivel chairs, armchairs that are wide and upholstered, folding chairs that are portable, children's chairs that are higher, and wheelchairs on casters for mobility. The tall bar chair known as a stool typically has no backrest.

History and culture

Chairs have been found in ancient Egypt and other early civilizations, where they were originally a mark of social rank, while most people sat on the ground or low beds. Chairs became widespread globally during industrialization, when mass production reduced their cost. The word itself is used metaphorically to mean office or authority—for example, 'the chair of the presidency'.

Design and health

Chair design is based on ergonomics, the study of how tools can best fit the human body. The goal is to distribute weight evenly, preserve the spine's natural shape, and reduce pain from prolonged sitting. Modern office chairs typically offer lumbar support and adjustable height.