The yelmo (helm) was the upper part of a suit of armour. Casco can refer to a hard had or a modern helmet (or also to the hooves of a horse) El yelmo era la parte superior de una armadura. El casco es lo que protege la cabeza de trabajadores, soldados, motociclistas etc. (Cascos se refiere tambien a las pezuñas de los caballos)