barbute
A type of visorless helmet, of 15th-century Italian design, including a T or Y shaped opening for the eyes and mouth.
Medium helmets weighing about six pounds occur in visored bassinets, salades, barbutes, armets and certain burganets.
Where it comes from
From Italian barbuta, perhaps because it left a wearer's beard (if any) visible.
Adapted from the Wiktionary entry barbute (CC BY-SA 4.0).