A description defining a female's backside, or booty. There's different classifications of ballparks:
Class 1: 'Single'- a small booty, but is there. Not flat, and if the right clothing is worn will be visible. rumpkin pumpkin
Class 2: 'Double'- a booty that stands between phat and not a lot. There's some shape, but will be argued by many of people if it's really a phat ass. It can be seen from the side usually.
Class 3: 'Triple'- a booty that is phat without question. It's universally accepted. Commonly used in rap videos. Can be seen from the back, side, and even in the front. A booty of great anticipation that pays off.