The art of shaping a mass of glass that has been softened by heat by blowing air into it through a tube.
A glass forming technique that involves inflating the molten glass into a bubble, or parison, with the aid of the blowpipe, or blow tube.
A person who blows glass is called a glassblower, glassmith, or gaffer. His reheating furnace is called a "glory hole"
Here you please find a photo to better understanding the mouth blown glass lampshades: