I just read the studies on dogs and pit bulls, I do not waste time with the effort to pretend that no one knows what they are.
As nations restrict pit bulls, the goof balls try to pretend that it is an international conspiracy against a unicorn like myth.
What is a pit bull?
The AKC: The American Pit Bull Terrier.
The ASPCA: The American Pit Bull Terrier and the American Staffordshire Terrier.
Chaca, a Pit Bull rescue group: The American Pit Bull Terrier, the American Staffordshire Terrier, and the Staffordshire Terrier.
About.com: American Pit Bull Terrier, American Staffordshire Terrier, American Bulldog, Boston Terrier, Boxer, Bull Terrier, Bullmastiff, English Bulldog, French Bulldog and Staffordshire Bull Terrier.
Miriam Webster: a dog (as an American Staffordshire terrier) of any of several breeds or a real or apparent hybrid with one or more of these breeds that was developed and is now often trained for fighting and is noted for strength and stamina.
Miami/Dade County: Any dog that possesses ANY of the AKC characteristics of an American Pit Bull Terrier, an American Staffordshire Terrier, or a Staffordshire Terrier. (BTW, one of the AKC characteristics of an American Pit Bull Terrier is a coat that is 'glossy, short, and stiff to the touch', apparently Dobermans and short-haired dachshunds are illegal in Miami/Dade County)
Google definitions: "a dog of an American variety of bull terrier, noted for its muscular build and often associated with ferocity."
Dogsbite.org: American pit bull terrier, American Staffordshire terrier, Staffordshire bull terrier, American bulldog and any other pure bred or mixed breed dog that is a combination of these dogs.
Wikipedia: as a generic term used to describe dogs with similar physical characteristics. The general public and news media consider a "pit bull" as one of several breeds including the Staffordshire Bull Terrier, American Pit Bull Terrier, American Staffordshire Terrier, Bull Terrier, or any mix thereof. Any dog that is mixed with a "bully breed" may also be called a "pit bull" including those that are descended from the English Bulldog, French Bulldog and Boston Terrier.
So everybody knows what 'pit bull' means, but they don't agree.
I can say, however, that the American Pit Bull Terrier, the American Staffordshire Terrier, and the Staffordshire Terrier seem to be on most lists.