In baseball a tag out, sometimes just called a tag, is a play in which the batter or baserunner is out because they are tagged by a ball that is in play while not standing on a base. Tag outs are the main way to retire baserunners who are not laible to be forced out. Runners attempting to steal a base are often thrown out which means that the catcher threw the ball to someone covering second base, and they tagged him out. Someone who is leading off a base too far might be picked off, that is, the pitcher throws to someone covering the base and they tag the runner out. Also after a runner tag up the only way to get him out is via a tag out.