Die
1) a tool to make threads on the OD of shafts.
2) Tools used to form and blank sheet metal parts. It typically consists of a punch and a die mounted in a punch press to punch or stamp out duplicate parts in quantity. The assembly is called a die set. Die making is a very high paying skilled craft. See also tool and die maker
3) Die cast where molten metal (usually zinc or aluminum) is injected under pressure into a mold. Similar to the process of plastic injection molding. Die making is a very high paying skilled craft.
4) The mold used in a forging operation. The process of machining these dies is called "die sinking" which is another high paying skilled craft of the machine trades.