thermionic tube definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
an electron tube having a cathode electrically heated in order to cause electron or ion emission
Also [Brit., etc.] thermionic valve
thermionic tube definition by American Heritage Dictionary
nounThe American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
An electron tube in which the source of electrons is a heated electrode.
thermionic tube - Science Definition
An electrical component, typically an electron tube, through which electric current flows via the emission of thermions from a heated cathode.