Noun
A die in the form of a metal plate.
(metalworking) A type of die for cutting screw threads on male fasteners; it is arranged in the form of a plate of tool steel with a graduated series of holes, each being the die opening for a certain size of screw. A predecessor of today's tap and die sets, it is now considered an antique type of tool, no longer in common use but still sometimes desirable as a collectible among tool collectors.
A metal plate that is part of a die.
Source: en.wiktionary.org