Bever

And, passing forward with furious affret, / Pierst through his bever and quite into his brow.

Source: wiktionary

He who lookes you in the face, ſaith he ſees you, though the reſt of your bodie be within your cloathes, and if you, being an ὁωλομάχος a cataphract in your proteſtantiſh πανοπλία [panoplía, suit of armour] should for fear pull downe your beuer before you come into the liſt, your Aduerſarie for all that might light vpon your (  ) vnleſſe you bring with you Giges his ring, ſo to make your ſelf inuiſible; [...]

Source: wiktionary

Some close helmets have a farther improvement called a bever, the bever when closed covers the mouth and chin, and either lifts up by revolving on the same pivots as the visor, or lets down by means of two or more pivots on each side near the jaws, in which case the bever consists of several laminæ or plates, one shutting over the other.

Source: wiktionary

Bid my subsiser carry my hackney to the buttery, and give him his bever; it is a civil and sober beast, and will drink moderately.

Source: wiktionary