All modern thorougbreds descend from one of three stallions: the Darley Arabian, the Godolphin Arabian and the Byerly Turk, together with around 35 mares. The first part of the horse's name is an indicator of the owner, the second part is an indicator of the horse's origin. The term "thoroughbred" was first used in the United States in an advertisement in a Kentucky gazette to describe a New Jersey stallion called Pilgarlick.
In the United States the registry for these horses is maintained by the Jockey Club.
Although the thoroughbred is primarily bred for racing, the breed is also used for show jumping and combined training due to their athleticism.
The typical thoroughbred stands 16 hands high, and is bay, chestnut, black or gray in color. The face and lower legs may be marked with white, but white will generally not appear on the body. A handful of non-albino Thoroughbreds have been born with white coats. For many years, the Jockey Club would not register a Thoroughbred as white; most such horses were registered as grays. However, the Jockey Club now recognizes white as a legitimate, though exceedingly rare, color.