The Whippet (also English Whippet or Snap Dog) is a dog breed of medium size. They are a sighthound breed that originated in England, where they descended from Greyhounds. Whippets today still strongly resemble a smaller Greyhound. The name is derived from an early 17th-century word, now obsolete, meaning 'to move briskly'. There has been continuity in describing Greyhound-types of different sizes: large, medium and small, as recorded in hunting manuals and works on natural history from the Middle Ages. They are generally healthy, and are not prone to the frequent ear infections, skin allergies, or digestive problems that can afflict other breeds.