Armor constructed of large sheets of metal hammered or otherwise formed into the shape of the wearer.
A misnomer born of mistakien victorian historians and popularized by fantasy role-playing games. Mail is defined as an armor made from metal rings. Plate mail, then, is self-contradictory. The correct historical term is plate or plate armor.
Warped out of plane (i.e. looks like a pringle chip - AKA 'tacoed'). A pringled ring is almost impossible to get straightened out without a hammer.
A process of chemically removing scales and oxides from metal by passing it through a chemical solution. See pickle.
An acidic solution used to clean the firescale that forms on the outside of some metals during heating. (see pickling)
Armour 'of proof' is made thick or hard enough to resist a shot from a bow or musket, depending on time period.