A league is a unit of measurement that traditionally refers to the distance a person can walk in an hour, approximately three miles or about 4.8 kilometers. It was commonly used in the past for navigation and mapping, especially in maritime contexts. In modern usage, the term "league" often refers to a group or association of individuals or organizations that come together for a common purpose, such as sports leagues like the National Football League or Major League Baseball. These leagues organize competitions and events, providing a structured environment for teams and players.