What's In A Name: American Pit Bull Terrier

The American Pit Bull Terrier is one of the "bully breeds" and is often called a pit bull. However, "pit bull" isn't a breed, it's a term used to describe several bull breeds including the American Pit Bull Terrier, the Bull Terrier, the American Staffordshire Terrier, and the Staffordshire Bull Terrier. 

Some people believe the American Pit Bull Terrier IS the American Staffordshire Terrier; others disagree. The confusion apparently began when the AKC made the decision in the early 1930s to give the American Pit Bull Terrier a new name – American Staffordshire Terrier -- to distance the breed from its pit-fighting past.

To further confuse the issue, the American Pit Bull Terrier is not recognized by the AKC, but the slightly smaller American Staffordshire Terrier is.

Source: Dr. Becker