In baseball, a pitchout is a ball that is intentionally thrown high and outside of the strike zone with the purpose of preventing a stolen base or thwarting a hit and run. The pitcher delivers the ball in such a manner for it to be unhittable and in a position where the catcher can quickly leap to his feet to catch it. A well-thrown pitchout will allow the catcher to receive the ball standing up as opposed to his usual squat, giving him a better line to throw to a base without the pitcher or the batter obstructing his vision or aim. Moreover, it is easier to throw a ball with more force from a standing position than it is from a squat, which is why most catchers leap to their feet when attempting to throw out a base stealer.
The pitchout is often called for when the battery believes that an existing baserunner is likely to attempt a steal, and forms one of the two (with the pickoff) main countermeasures a pitcher can take against a potential stealer. A runner attempting to steal on a pitchout will have an extremely difficult time beating the throw to second base and almost no chance of stealing third barring a mistake by the catcher or the third baseman.
The pitchout is also used against the hit and run. As the pitch is unhittable, the runner will have to attempt a straight steal, and for the reasons described above will usually fail.
A pitchout is thrown in around the same location as an intentional ball, but differs in that a pitchout is thrown harder to give the catcher the most time to throw out the baserunner. Of course, a pitchout is technically an intentional ball, but the term is not used to describe the pitchout in conversation.
See also: List of baseball pitches