This article is a list of horse and pony breeds with articles on Wikipedia, and also includes terms for that are not necessarily standardized breeds but are often labeled as breeds. While there is no scientifically accepted definition of the term "breed", a breed is generally defined as having distinct true-breeding characteristics over a number of generations. Its members may be called "purebred". In most cases, bloodlines of horse breeds are recorded with a breed registry. The concept is somewhat flexible in horses, as open stud books are created for recording pedigrees of horse breeds that are not yet fully true-breeding.