An AKC pit bull is a pit bull that comes with papers certified by the American Kennel Club. A pit bull with AKC-certified papers simply means that the club has registered the parents of the pit bull, and the animal in question is of the breed specified.
Ownership of AKC papers is advantageous for many breeds in the United States. By having these papers, an owner is certain that the animal purchased is the legitimate offspring of its parents. Also, AKC papers give the owner the ability to enter the animal in certain breed-specific events that the AKC hosts, such as shows and agility contests.