from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An electron tube from which all or most of the gas has been removed, permitting electrons to move with low interaction with any remaining gas molecules.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An electrical device containing a heated filament inside an evacuated container (generally a glass tube) and used to produce rectification (a diode vacuum tube), amplification or other functions.
from the GNU version of the Collaborative International Dictionary of English
- n. any tube used in electronic devices, containing a vacuum and used to control the flow of electrons in a circuit, as a vacuum diode, triode, tetrode, or pentode.
from The Century Dictionary and Cyclopedia
- n. A sealed glass tube employed to examine the effects of a discharge of electricity through air or other gas rarefied or exhausted to the required degree.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope
Sorry, no etymologies found.
Considering their atmosphere, it's unlikely they ever would invent it for themselves — imagine how thick a vacuum tube has to be, how strong a pump you need!