Derby /(?; usually ? in Eng.; 85)/

Der·by

Derby

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.
  2. A stiff felt hat with a dome-shaped crown.

Phrases & Compounds
Derby Day
the day of the annual race for the Derby stakes, -- Wednesday of the week before Whitsuntide.