Once a batter steps up to the plate an area called the strike zone is formed. This is the area that is over home plate and from the height of the bottom of the batter’s kneecaps to the midpoint between his shoulders and his belt.
Any pitch that passes through that area (as determined by the umpire) is a strike, even if it hits the batter. Also a pitch is a strike if the batter swings at the pitch and misses—regardless of its location. Another way to get a strike is to hit a foul ball.
Any pitch that does not pass through the strike zone and is not swung at by the batter is called a ball.
After a batter attains three strikes, he has struck out (one major exception being that a foul ball with two strikes does not count as anything). After four balls the batter is automatically allowed to move to first base—this is called a walk.
The number of balls and strikes against a batter is called the count. The count is said aloud by the umpire before every few pitches, and is often displayed on the scoreboard (or on the corner of your TV, if you are watching the game from home). The count is stated ‘number of balls’ and ‘number of strikes,’ for example, a count of two balls and one strike would be said “two and one.”
Rule 2 Strike, Rule 2 Ball