Incandescent light bulbs consist of an air-tight glass enclosure (<answer>the envelope</answer>, or bulb) with a filament of tungsten wire inside the bulb, through which an electric current is passed. Contact wires and a base with two (or more) conductors provide electrical connections to the filament. Incandescent light bulbs usually contain a stem or glass mount anchored to the bulb's base that allows the electrical contacts to run through <answer>the envelope</answer> without air or gas leaks. Small wires embedded in the stem in turn support the filament and its lead wires.
What is the name of the air-tight glass enclosure in an incandescent bulb?
the envelope