World Series
In short
The annual championship series of Major League Baseball played between the winners of the American League and the National League. The winner receives the Commissioner's Trophy after winning a best-of-seven series.
In plain words
It is the final tournament in professional baseball. Two top teams play against each other in several games. The first team to win four games becomes the champion.
A simple example
If the Los Angeles Dodgers play the New York Yankees, they will compete in up to seven games to decide who wins the title.
Why it matters
It decides the best baseball team in North America. Winning the series is the highest achievement for any professional baseball player.
Easy to mix up
Do not confuse this with the World Cup in football or other international sports tournaments.