A chair is a piece of furniture with a raised surface supported by legs, commonly used to seat a single person. Chairs are supported most often by four legs and have a back; however, a chair can have three legs or can have a different shape. Chairs are made of a wide variety of materials, ranging from wood to metal to synthetic material (e.g. plastic), and they may be padded or upholstered in various colors and fabrics, either just on the seat (as with some dining room chairs) or on the entire chair.
A chair may or may not have armrests; chairs with armrests are termed “armchairs”. In French, a distinction is made between fauteuil and chaise, the terms for chairs with and without armrests, respectively. In Germany, an armchair was once called a Krankensessel, or sick-chair, because it was intended for people who were too ill to stand or sit without extra support.
A stool is one of the earliest forms of seat furniture. It bears many similarities to a chair. It consists of a single seat, for one person, without back or armrests (in early stools), on a base of either three or four legs. A stool is generally distinguished from chairs by their lack of arms and a back. Variants exist with one, two or five legs and these various stools are referred to by some people as “backless chairs”.