noun.
A late-medieval light helmet with a neck guard and movable visor.
The Century Dictionary and Cyclopedia
noun.
The most complete and perfect defensive head-covering of the middle ages, introduced about 1450, and remaining in use until the abandonment of the closed headpiece, more than a century later.
the GNU version of the Collaborative International Dictionary of English
noun.
A kind of helmet worn in the 14th, 15th, and 16th centuries.