Sacrifice Fly

In baseball, a sacrifice fly is a batted ball that satisfies four criteria:

• There are fewer than two outs when the ball is hit.
• The ball is hit to the outfield (fair or foul), or to infield foul territory.
• The batter is put out because an outfielder (or an infielder running in the outfield, or foul territory) catches the ball on the fly (alternatively if the batter would have been out if not for an error or if the outfielder drops the ball and another runner is put out).
• A runner who is already on base scores on the play.

It is called a "sacrifice" fly because the batter presumably intends to cause a teammate to score a run, while sacrificing his own ability to do so.