A league is a group of teams or players who compete against each other in organized games or matches. When you join a little league baseball team or a soccer league, you're part of a group where teams play each other regularly, often following a schedule and keeping track of wins and losses. Professional sports like baseball, basketball, and football all have leagues: Major League Baseball, the NBA, the NFL.

The word comes from an old idea of people joining together for a common purpose. Countries might form a league to work together, like when the League of Nations was created after World War I to help prevent future wars. People also use the phrase in league with to mean working together, sometimes secretly: “The two students were in league to pull off the perfect surprise party.”

You might also hear league used as a way to describe someone's level of ability or status. If something is out of your league, it means it's beyond your current skill level or reach. A beginning chess player might say that competing against a grandmaster is out of their league. But here's the thing: leagues change. With practice and determination, what's out of your league today might be exactly where you belong tomorrow.

A league is also an old unit of distance, roughly three miles, though people rarely use it this way anymore except in old stories and the phrase 20,000 Leagues Under the Sea.