Infield Fly Rule 

If there are runners on first and second(Or the bases are loaded) and less then two outs when the batter hits a pop-up to the infield, he is automatically ruled out to prevent fielders from dropping the ball on purpose to try to turn a double play.

Since the bases were loaded with no one out, that easy pop-up became an infield fly, so the third baseman doesn't need to catch it.

Infield Fly Rule by birdboy2000 July 16, 2004

Infield Fly Rule 

Baseball sexual metaphor for when there's an unequal ratio of males and females at a party and one member of the dominant group leaves to create an equal ratio.

John called the infield fly rule at the party and left so it didn't turn into a sausage fest.

Infield Fly Rule by Shazam814 December 10, 2009

Infield Fly Rule 

Somebody explain this

Infield Fly Rule by Anonymous October 17, 2003