The word horse race may refer to:
A horse race is a competitive event in which horses compete in groups under the guidance of jockeys. Horse races are primarily flat races, but there are also steeple chases and hurdle races. Historically, horse racing was only open to wealthy and noblemen, but the practice spread to the lower classes as betting became more popular. In the 19th century, wagering on horses was centralized at racetracks in the form of a pari-mutuel system, in which all bets are placed in the same pool and the money distributed to the winners. Currently, all horse races are organized by national or international governing bodies and have a grade assigned to them, based on the quality of the field, the number of runners, and the size of the purse (prize money). A higher-ranked race is a graded race. Horse races are also classified by the distance they cover. The oldest horse race is the Derby, which was first run in 1875 and is a 2-mile race on dirt tracks. Modern horse races can be up to 10 miles long. The highest-ranked horse races are the Triple Crown races, including the Preakness and Belmont Stakes, which are both grade I races. Other races are designated as grade II, III, and IV, with the latter being the lowest-ranked. The grading of races is determined by a governing body and may be upgraded or downgraded if a variety of factors, such as weather conditions or the state of the turf, are considered.