racehorse(n = noun.animal) bangtail, race horse - a horse bred for racing;
is a kind of equus caballus, horse
has particulars: thoroughbred, pony, yearling, two-year-old horse, two year old, three-year-old horse, three year old, dark horse, mudder, nonstarter, pacemaker, pacer, pacesetter, trotter, trotting horse

racehorse, n. a horse bred or kept for racing.

N  carrier, porter, bearer, tranter, conveyer, cargador, express, expressman, stevedore, coolie, conductor, locomotive, motor, beast, beast of burden, cattle, horse, nag, palfrey, Arab, blood horse, thoroughbred, galloway, charger, courser, racer, hunter, jument, pony, filly, colt, foal, barb, roan, jade, hack, bidet, pad, cob, tit, punch, roadster, goer, racehorse, pack horse, draft horse, cart horse, dray horse, post horse, ketch, Shetland pony, shelty, sheltie, garran, garron, jennet, genet, bayard, mare, stallion, gelding, bronco, broncho, cayuse, creature, critter, cow pony, mustang, Narraganset, waler, stud, Pegasus, Bucephalus, Rocinante, ass, donkey, jackass, mule, hinny, sumpter horse, sumpter mule, burro, cuddy, ladino, reindeer, camel, dromedary, llama, elephant, carrier pigeon, pallet, brace, cart, dolley, support, fork lift, carriage, ship, equine, asinine.