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Related to thermionic tube: Thermionic device
thermionic tube[‚thər·mē′än·ik ′tüb]
An electron tube that relies upon thermally emitted electrons from a heated cathode for tube current. Also known as hot-cathode tube.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.