An eleganc office chair , or desk chair , is a type of chair that is designed for use at a desk in an office. It is usually a swivel chair , with a set of wheels for mobility and adjustable height. Modern office chairs typically use a single, distinctive load bearing leg (often called a gas lift ), which is positioned underneath the chair seat. Near the floor this leg spreads out into several smaller feet, which are often wheeled and called castors . Office chairs were developed around the mid-19th century as more workers spent their shifts sitting at a desk, leading to the adoption of several features not found on other chairs.