casque

noun

1. an open, conical helmet with a nose guard, commonly used in the medieval period.
2. any helmet-shaped head covering.
3. Zoology. a process or formation on the head, resembling a helmet.

noun

1. zoology a helmet or a helmet-like process or structure, as on the bill of most hornbills

n.

“armor for the head,” 1570s, from French casque (see cask).