Fair ball


In baseball, a fair ball is a batted ball that entitles the batter to attempt to reach first base. By contrast, a foul ball is a batted ball that does not entitle the batter to attempt to reach first base. Whether a batted ball is fair or foul is determined by the location of the ball at the appropriate reference point, as follows:
If the ball is on or above fair territory at the appropriate reference point, it is fair; else it is foul. Fair territory or fair ground is defined as the area of the playing field between the two foul lines, and includes the foul lines themselves and the foul poles. However, certain exceptions exist:
On a fair ball, the batter attempts to reach first base or any subsequent base, runners attempt to advance and fielders try to record outs. A fair ball is considered a live ball until the ball becomes dead by leaving the field or any other method.