sallet
A type of light spherical combat helmet used in the 15th century.
historical
At Hampton Court, sallets for archers on horseback, sallets with grates, and old sallets with vizards: At Windsor, salettes and skulls: At Calais, saletts with vysars and bevers, and salets with bevers.
Where it comes from
From Middle French salade, from Spanish celada, thought to be from Latin caelāta (“ornamentally engraved [helmet]”) (although the Latin word is not attested in this sense).
Adapted from the Wiktionary entry sallet (CC BY-SA 4.0).