ventail

Synonym of aventail (“mail curtain or flap, on a helmet or a mail coif, that protects the lower face and neck”).

Having unhorsed this enemy and hacked him into submission, the knight rips off his foe's helmet and turns down the mail ventail (protecting the vulnerable throat), perhaps pounds the fellow's face a bit with the pommel of his sword; ...

Finally, the Carolingian byrnie might have had a mail ventail, or bib, hanging from the neck that, when raised and attached to the helmet, provided neck and lower face protection. The ventail is specifically mentioned twice in the ...

The movable front part of a medieval helmet, originally including the visor but later specifically the separate lower section.

A comely knight, all arm'd in complete wize, / Through whose bright ventayle lifted vp on hye / His manly face [...] Lookt foorth [...].

The helmet, in its improved state, was composed of two parts; the headpiece, which was strengthened within by several circles of iron; and the visor or ventail, which (as the names imply) was a sort of grating to see or breathe through, so contrived as by sliding in a groove, or turning on a pivot, to be raised or lowered […]

A vent or breathing-hole in a medieval helmet, for the admission of air.

398. ventayles : a pun on ventails, 'something acting as a sail or fan', and ventails, the air holes or vents in the vizor of a helmet.

Here would be Sir Gawaine sitting on his antagonist's chest, and finishing him off, through the ventails of his helm, with the long sharp poniard called the Mercy of God. There would be a couple of knights who had suffocated themselves in their own helms during the course of a battle, a misfortune which frequently happened in those days of violent exercise and small vents.