High Quality Content by WIKIPEDIA articles! In sports, a cap is a metaphorical term for a player`s appearance on a select team, such as a national team. The term dates from the practice in the United Kingdom of awarding a cap (an item of headgear) to every player in an international match of association football. In the early days of football, the concept of each team wearing a set of matching shirts had not been universally adopted, so each side would distinguish itself from the other by wearing a specific sort of cap.