What is "stolen base"

n. (context baseball English) A play where a runner on any base attempts to run to the next base while the pitcher pitches for a batter; the runner must make it to the next base before the ball does, or they are out.

In baseball, a stolen base occurs when a runner advances to a base to which he is not entitled and the official scorer rules that the advance should be credited to the action of the runner. The umpires determine whether the runner is safe or out at the next base, but the official scorer rules on the question of credit or blame for the advance under Rule 10.

A stolen base most often occurs when a baserunner advances to the next base while the pitcher is pitching the ball to home plate.

Successful base stealers are not only fast but have good baserunning instincts and timing.