What does EGUN mean or stand for ?

An electron gun is a device that releases a thin beam of negatively charged particles.These are released by a cathode and are attracted by the positive anode inside a vacuum tube.These are used in any CRT television and computer monitors.

In our everyday lives we see a variation of this in the form of a tubelight. The same vacuum tube is filled with an inert gas,and when the electron beam ionizes the gas,its begins to glow bright.!