In baseball statistics, a putout (PO) is awarded to a defensive player who records an out by one of the following methods:Tagging a runner with the ball when he is not touching a base
Catching a batted or thrown ball and tagging a base to put out a batter or runner
Catching a thrown ball and tagging a base to record an out on an appeal play
Catching a third strike
Catching a batted ball on the fly
Being positioned closest to a runner called out for interference
An attempted putout at first base.
Jake Beckley, all-time career leader in putouts among major-league players
In baseball, an out occurs when the umpire rules a batter or baserunner out. When a batter or runner is out, they lose their ability to score a run and must return to the dugout until their next turn at bat. When three outs are recorded in a half-inning, the batting team's turn expires.
A 1911 American Tobacco Company baseball card illustrating a baserunner being tagged out at third base