A
chair is a piece of
furniture with a raised surface used to sit on, commonly for use by one person. Chairs are most often supported by four legs and have a back; however, a chair can have three legs or could have a different shape.
A chair without a back or arm rests is a
stool, or when raised up, a
bar stool. A chair with arms is an
armchair and with folding action and inclining footrest, a
recliner. A permanently fixed chair in a train or
theater is a
seat or, in an airplane,
airline seat; when riding, it is a
saddle and
bicycle saddle, and for an automobile, a
car seat or
infant car seat. With wheels it is a
wheelchair and when hung from above, a
swing.
A chair for more than one person is a
couch, sofa, settee, or "loveseat"; or a
bench. A separate footrest for a chair is known as an
ottoman, hassock or
pouffe.