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.