Derby \Der"by\ (?; usually ? in Eng.; 85), 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.
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{Derby Day}, the day of the annual race for the Derby stakes,
-- Wednesday of the week before Whitsuntide.
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2. A stiff felt hat with a dome-shaped crown.
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