Baseball is a sport contested between two teams of nine players on a baseball field in which a defensive player (a pitcher) throws a hard, fist-sized ball toward an area proximate to an offensive player (a batter), who, using a smooth, cylindrical bat (fabricated, in professional baseball, exclusively of wood), attempts to strike the ball in order that it should not be caught by fielders periperhal to and behind the pitcher. A team scores only when batting, by advancing a player counter-clockwise past a series of four markers (bases) arranged at the corners of a diamond, the last of which (home plate) marks the location over which a pitch is thrown.
The game is most often played in nine innings, in each of which each team tries to score runs before the fielding team records three outs (retiring three opposing batters, by catching a batted ball in the air, tagging a player prior to his reaching a base [or, under specific circumstances, advancing the ball to the base to which the offensive player runs], or by striking out, an opposing batter by throwing three strikes), after which the teams exchange positions; in every case, the team then defending possess the ball, in contrast to many other ball sports. Baserunners touch the bases in sequence as a result of one or more plays, and the team to have scored more runs over nine innings is considered as the winner.
The sport, a derivative of several British stick-and-ball games, having been popularized in the United States, is now popular in North, Central, and South America, the Caribbean, and Asia, and is played in organized professional or quasi-professional leagues in the United States, Japan, Puerto Rico, South Korea, Taiwan, Cuba, Mexico, Panama, and Venezuela; it remains culturally significant in the United States, where it is often referred to as the national pastime.