A cap is an appearance for a select team, such as a school, county or international team in sports. The term dates from the practice in the United Kingdom of awarding a cap (meaning an item of headgear) to every player in an international match of Association Football; however, the act of awarding a cap is now international and is applied to other sports. The practice was first approved on May 10, 1886 for Association Football, after a proposal made by N. L. Jackson, founder of Corinthians F.C.:

That all players taking part for England in future international matches be presented with a white silk cap with red rose embroidered on the front. These to be termed International Caps.

Today it might seem an unusual and perhaps even a bizarre practice to present a player with an actual cap but in the early days of football the concept of each team wearing a set of matching shirts had not been universally adopted, with the result that a team's players would often take the field in a variety of different coloured shirts, and each side would distinguish itself from the other by wearing a specific sort of cap or other headgear. An early illustration of the first international football match between England and Scotland in 1872 shows the Scottish players wearing cowls and the English wearing a variety of school caps.

Actual caps are not given any more (caps for friendly matches still exist, and each player gets one cap per international competition), but the term "cap" for an international or other appearance has been retained. Thus, a cap is awarded for each game played and so a player who has played x games, for the team, is said to have been capped x times or have won x caps.