Source : Webster's Revised Unabridged Dictionary (1913)

Casque \Casque\, n. [F. casque, fr. Sp. casco See {Cask}.]
   A piece of defensive or ornamental armor (with or without a
   vizor) for the head and neck; a helmet.

         His casque overshadowed with brilliant plumes.
                                                  --Prescott.

Source : WordNet®

casque
     n : (15-16th century) any armor for the head; usually ornate
         without a visor