The American Pit Bull Terrier (APBT) is a medium-sized, solidly built, short haired dog whose early ancestors came from England and Ireland. It is a member of the molosser breed group. The American Staffordshire Terrier and The American Pit Bull Terrier (APBT) by breed are from the same lineage; Staffordshire was the name given by American Kennel Club (AKC), and American Pit Bull Terriers by United Kennel Club (UKC). The two breeds are similar in size. As compared to the Staffordshire Bull Terrier, an English breed, the American Pit Bull Terrier is by margins of 6–8 inches (15–20 cm) in height and 25–35 pounds (11–16 kg) in weight the larger of the two.
The dog was bred first to bait bulls and bears. When bear-baiting and bull-baiting were deemed inhumane, rat-baiting and dog-baiting became more popular. The APBT Breed was used in both sports, and its prevalence in being put in pits with rats, or other dogs led to “pit” being added to its name.