Wiktionary
harness racing
n. A form of horse racing in which the horses race in a specified gait, usually pulling two-wheeled carts called sulky.
WordNet
harness racing
n. a horse race between people riding in sulkies behind horses that are trotting or pacing [syn: harness race]
Wikipedia
Harness racing
Harness racing is a form of horse racing in which the horses race at a specific gait (a trot or a pace). They usually pull a two-wheeled cart called a sulky, although in Europe racing under saddle (trot monté in French) is also conducted.