Wiktionary
n. (context horse racing English) A breed of horse bred specifically for harness racing
Wikipedia
The Standardbred is an American horse breed best known for its ability in harness racing, where members of the breed compete at either a trot or pace. Developed in North America, the breed can trace its bloodlines to 18th-century England. The Standardbred is recognized worldwide. They are solid, well-built horses with good dispositions. In addition to harness racing, the Standardbred is used for a variety of equestrian activities — including horse shows and pleasure riding — particularly in the midwestern and eastern United States, and southern Ontario.
Usage examples of "standardbred".
Thoroughbred, standardbred, and quarter-horse racing, while exciting, led to heartbreak back at the shed row.
The best of them do have some thoroughbred or standardbred or Morgan blood in them, if you trace back their bloodlines.