n. 1. A race for three-old horses, run annually at Epsom (near London), for the Derby stakes. It was instituted by the 12th Earl of Derby, in 1780. [ 1913 Webster ]
Derby Day, the day of the annual race for the Derby stakes, -- Wednesday of the week before Whitsuntide. [ 1913 Webster ]
2. A stiff felt hat with a dome-shaped crown. [ 1913 Webster ]