The question is not straightforward. At Pitbulls.org, we try to keep the focus on the American Pit Bull Terrier, as this helps simplify things, so people know what we are talking about when we say "pit bulls." Most, if not all, of our articles are based on this assumption. So you can read our history of the American Pit Bull Terrier for one answer to the question posed in the title.
But the APBT is not the only dog referenced when people say "pitbull," and can include the Staffordshire Bull Terrier and the American Staffordshire Terrier, but also many dogs that only bear some resemblance, and this presents some confusion. The problem is particularly acute in media reports. Because of this confusion, many situations said to involve pit bulls really don't, and without a proper DNA test, it's nearly impossible to accurately spot a true Pit Bull. Can YOU find the Pit Bull?
The question also becomes a problem when dealing with Breed Specific Legislation or in regards to apartments that don't accept people with pit bulls and airlines that don't allow travel. In order to discriminate and enforce rules, people have to have an answer to this question. And in order to be "safe", they draw a broader stroke that goes beyond the truth.
Sometimes boxers are thrown into the mix. Sometimes the American bull dog is called a pit bull. Even some Labrador Retrievers can have characteristics that cause people to jump to conclusions.
So what is a pit bull? Calling a dog a pit bull should be limited to the main three we already mentioned: American Pit Bull Terrier, Staffordshire Bull Terrier, and the American Staffordshire Terrier (Although we will continue to maintain a focus on the ABPT.) In other words, those with some terrier in their blood. We know this isn't the only definition out there, but it is the one that actually gives a consistant, meaningful barrier to the phrase "Pit Bull." Some will want to apply the label to many breeds in the Molosser breed group, such as bull mastiffs and boxers, but Great Danes also fall under the Molosser category.
Do you agree? Disagree? What do you think constitues a "pit bull?"