What is the meaning of Punty?

A metal rod used in the glassblowing process. After a glass vessel has been blown to approximate size and the bottom of the piece has been finalized, the rod, which is tipped with a wad of hot glass, is attached to the bottom of the vessel to hold it while the top is finalized. It often leaves an irregular or ring-shaped scar on the base when removed, called the pontil mark.

Source: wiktionary.org