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. Until 1800 both hand knitting and machine knitting were used to produce socks, but after 1800, machine knitting became the predominant method.
One of the roles of socks is absorbing perspiration. The foot is among the heaviest producers of sweat in the body, as it can produce over 0.25 US pints (0.12 l) of perspiration per day; socks help to absorb this sweat and draw it to areas where air can evaporate the perspiration. In cold environments, socks made from wool insulate the foot and decrease the risk of frostbite. Socks are worn with sport shoes (typically white-coloured socks) and dress shoes (typically dark-coloured socks). 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.