Softball is an activity that came from baseball, in which a ball, eleven to twelve inches (or rarely, 16 inches) (28 to 30.5 centimeters) in circumference, is thrown (pitched) underhand by a player called a pitcher and hit by an offensive player called a batter with a round, smooth stick called a bat (usually wooden, metal or composite). Scoring is accomplished by the batter running and touching a series of three raised markers on the ground called bases, and then touching the final base, called home plate.

In softball there is an offensive team, the team that bats , and a defensive team, the team that occupies the field. Both teams switch between offense and defense. The determining of which team is offense and which is defense is based on a series of outs. The goal for the defensive team is to receive three outs. Outs can be received in many ways. One way to get an out (for the defensive team) is by having a defensive player catch a ball hit by an offensive player in the air. Another way is by having a defensive player throw the ball to another defensive player who is standing on a base; this must be accomplished before the offensive player reaches that base. A third is by having the pitcher strike out the batter.

A strikeout is when the pitcher throws three strikes to the batter. A strike is given when there is a good pitch, which the batter does not hit, or when the batter swings at the ball and misses it. The batter is also given four balls. A ball is a bad pitch. If the batter receives four balls she gets to go to the first base, this is called a walk.

Softball has a set number of innings, usually seven or nine. An inning is one series of both teams playing offense and defense. At the end of the set number of innings the team with the highest score wins.

Baseball is sometimes referred to as hardball to distinguish it from softball, but differs from it in several ways (see Comparison of baseball and softball). This article assumes no knowledge of baseball.

The sport's governing body, the International Softball Federation holds world championships, held every four years, in several categories.

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