Terminology
The Thoroughbred is a distinct breed of horse, although people sometimes refer to a purebred horse of any breed as a thoroughbred. The term for any horse or other animal derived from a single breed line is purebred. While the term probably came into general use because the English Thoroughbred's General Stud Book was one of the first breed registries created, in modern usage horse breeders consider it incorrect to refer to any animal as a thoroughbred except for horses belonging to the Thoroughbred breed. Nonetheless, breeders of other species of purebred animals may use the two terms interchangeably, though thoroughbred is less often used for describing purebred animals of other species. The term is a proper noun referring to this specific breed, though often not capitalized, especially in non-specialist publications, and outside the US. For example, the Australian Stud Book, The New York Times, and the BBC do not capitalize the word.
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