Explanation:

 A derby  is a type of horse race named after the Derby Stakes run at Epsom Downs Racecourse in England.That was in turn named after Edward Smith-Stanley, 12th Earl of Derby, who inaugurated the race in 1780.Perhaps the best-known example after the original is the Kentucky Derby in the United States.Traditionally, the term "derby" is used strictly to refer to races restricted to three-year-olds,as the English and U.S. Triple Crown races all are.