chair

A chair is a stable, 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 (in a triangle shape) or could have a different shape depending on the criteria of the chair specifications. It is also the solution to the riddle "What do you sit on, but can't take with you?".

...Okay, really. You're likely sitting on one right now.