Baseball is a sport played between two teams usually of nine players each. It is a bat-and-ball game in which a pitcher throws (pitches) a hard, fist-sized, leather-covered ball toward a batter on the opposing team. The batter attempts to hit the baseball with a tapered cylindrical bat, made of wood (as required in professional baseball) or a variety of other materials (as allowed in many nonprofessional games). A team scores runs only when batting, by advancing its players—primarily via hits—counterclockwise past a series of four markers called bases arranged at the corners of a ninety-foot square, or "diamond." The game, played without time restriction, is structured around nine segments called innings. In each inning, both teams are given the opportunity to bat and score runs; a team's half-inning ends when three outs are recorded against that team.

Baseball on the professional, amateur, and youth levels is popular in North America, Central America, parts of South America, parts of the Caribbean, and East Asia. The modern version of the game developed in North America beginning in the eighteenth century. The consensus of historians is that it evolved from earlier bat-and-ball games, such as rounders, brought to the continent by British and Irish immigrants. By the late nineteenth century, baseball was widely recognized as the national sport of the United States. The game is sometimes referred to as hardball in contrast to the very similar game of softball.

In North America, professional Major League Baseball teams are divided into the National League (NL) and American League (AL). Each league has three divisions: East, West, and Central. Every year, the champion of Major League Baseball is determined by playoffs culminating in the World Series. Four teams make the playoffs from each league: the three division leaders, plus one wild card team. A wild card team is the team with the best record among the teams in the league that have not already advanced to the playoffs. In the National League, the pitcher is required to bat, per the traditional rules. In the American League, there is a tenth player, a designated hitter, who bats for the pitcher. Each major league team has a "farm system" of minor league teams at various levels. These teams allow younger players to gain experience against opponents with similar levels of skill. -Wikipedia.org