Armet

n. medieval light helmet totally enclosed having a neck guard secured under the chin and a movable visor

Armet is the name of a type of helmet developed in the 15th century, most likely in Italy. It was distinguished by being the first helmet of its era to completely enclose the head while being compact and light enough to move with the wearer. The typical armet consisted of four pieces: the skull, the two cheek plates, and the visor. A multi-part reinforcement for the bottom half of the face, known as a wrapper, was sometimes added, and its straps attached to a metal disc at the base of the skull piece called a rondel. It reached its height of popularity during the 15th and 16th centuries when knights in medieval Europe wore plate armor into battle. Movable face and cheek pieces allowed the wearer to close the helmet, thus fully protecting the head from blows. The armet consisted of a skull piece, two hinged cheek pieces which lock at the front, and a visor piece. Armets have often been confused with close helmets, and the two names can now be used almost interchangeably when referring to either form of helmet. Close helmets had a full visor and bevor (a chin/neck guard); the visor pivoted up and down by means of bolts attached to the side of the skull piece. Slightly different in design, armets had hinged cheek pieces which opened at the front of face backward. Note the similarities between the armet above and the close helmet to the lower left.
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Noun
1. a medieval helmet with a visor and a neck guard
(hypernym) helmet
(part-holonym) body armor, body armour, suit of armor, suit of armour, coat of mail, cataphract

(n.)
A kind of helmet worn in the 14th, 15th, and 16th centuries.
  

The dominant helmet during much of the 15th century, the Armet gradually evolved into the first truly international style of helmet, the close helmet. Armets were built of a snug-fitting bowl that came to just above the ears, fitted with cheek plates that attached by hinges to this bowl. Usually the chin pieces clasp in the front and secure in the back along a strip of steel that extends from the shallow skull bowl. The bowl itself is often reinforced with an additional layer of steel across the brow, and a visor fills in around the nose and eyes to make an exceptionally functional closed helmet. For some unknown reason, a disc of metal was sometimes attached to the back of these helmets; the purpose of this rondel is unknown. The armet succeeded the bascinet as the most common helmet in Europe, taking elements from the great bascinet . They were exceedingly popular in Italy, France and England, while the Sallet enjoyed great popularity in those regions and also in the German lands as well.