pot metal

noun4

1. •
   The metal from which iron pots are made, different from common pig iron.
2. •
   An alloy of copper with lead used for making large vessels for various purposes in the arts.

   • Copper, with about a fourth of its weight of lead, forms pot-metal, used by the ancients for their coins. — 1819
3. •
   Synonym of monkey metal.
4. •
   A kind of stained glass, the colours of which are incorporated with the melted glass in the pot