Pit bull is a word used to describe several breeds of dog. This includes the American Pit Bull Terrier, American Staffordshire Terrier, American Bully and Staffordshire Bull Terrier, and dogs with a mix of these breeds. In some locations, the modern American Bulldog and Bull Terrier are described as a "pit bull-type dog". Pit bull can also mean dogs that were known as "bull terriers" before the development of the modern Bull Terrier in the early 20th century.
These dogs were bred by crossing bulldog breeds and terriers. Pit bulls are very strong and can pull many times their weight. They were also bred for dog fighting. The place where such dogs fought was called a pit. As such dogs can be dangerous, very often a special permit is needed to breed or to own them. Some places or countries may have forbiddden their use.