An evacuated glass bulb containing a metal filament which is heated by electrical resistance to produce light.
An article that resembles such a bulb and converts electricity to light by any process.
Used in reference to the sudden arrival of a realization, an inspiration, an idea, or the like.
A type of electron tube that controls electron current through vacuum between electrodes within a sealed container, usually of glass or metal and often designed to be easily installed in and removed from the equipment in which it is used.