Bull and terrier was a common name for crossbreeds between bulldogs and terriers in the early 1800s. Other names included half-and-halfs and half-breds. It was a time in history when, for thousands of years, dogs were classified by use or function, unlike the modern pets of today that were bred to be conformation show dogs and family pets. Bull and terrier crosses were originally bred to function as fighting dogs for bull- and bear-baiting, and other popular blood sports during the Victorian era. The sport of bull baiting required a dog with attributes such as tenacity and courage, a wide frame with heavy bone, and a muscular, protruding jaw. By crossing bulldogs with various terriers from Ireland and Great Britain, breeders introduced "gameness and agility" into the hybrid mix.

Terrier is a type of dog originally bred to hunt vermin. A terrier is a dog of any one of many breeds or landraces of the terrier type, which are typically small, wiry, game, and fearless. There are five different groups of terrier, with each group having different shapes and sizes.