casque n 1: (15-16th century) any armor for the head; usually ornate without a visor
Casque \Casque\ (k[.a]sk), 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. [1913 Webster] His casque overshadowed with brilliant plumes. --Prescott. [1913 Webster]