A sock is an item of clothing worn on the feet and often covering the ankle or some part of the calf. Some type of shoe or boot is typically worn over socks. In ancient times, socks were made from leather or matted animal hair. In the late 16th century, machine-knit socks were first produced.

One of the roles of socks is absorbing perspiration. In cold environments, socks made from wool insulate the foot and decrease the risk of frostbite. In addition to the numerous practical roles played by socks, they are also a fashion item, and they are available in myriad colours and patterns.