The whippet is a British breed of medium-sized dog, of the sighthound type, related to the larger greyhound and the smaller Italian greyhound. Apart from the differences in height, the whippet closely resembles these two breeds; it has sometimes been described as "the poor man's greyhound". It is kept as a companion dog, for competitive showing, for amateur racing as well as lure coursing. It has the highest running-speed of any breed in its weight and size range, and may have the fastest idle-to-running acceleration of any dog.The breed's name, ‘whippet’, is derived from an early seventeenth-century word (now obsolete) meaning "to move briskly".There has been some continuity in describing greyhound-types of different sizes — large, medium and small, recorded in hunting manuals and works on natural history from the Middle Ages. Edward of Norwich, 2nd Duke of York, confirmed in his early 15th-century translation of (and additions-to) an original, late 14th-century French Livre de chasse the advantages of maintaining the ‘great’, the ‘middle’, and the ‘small size of greyhound’ for different sorts of game. The English physician and academic John Caius refers in his 16th century De Canibus Britannicus to lesser as well as greater sorts of Leporarius, Grehounde (greyhound) and notably to a type which has been connected to the whippet, the tumbler, a lesser sort of mungrell greyhounde and excellent warren dog for catching rabbits, also recorded by the early 19th-century Scottish curator and editor Thomas Brown. The Victorian English writers describe an emerging modern breed of whippet, or snap-dog, bred for catching rabbits, coursing competitions, straight rag-racing, and for the novel show fancy. [2]