Dictionary.com
definitions

tetrode

[te-trohd]
noun Electronics.
  1. a vacuum tube containing four electrodes, usually a plate, two grids, and a cathode.

Origin of tetrode

First recorded in 1900–05; tetr- + -ode1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for tetrode

tetrode

noun
  1. an electronic valve having four electrodes, namely a cathode, control grid, screen grid, and anode
  2. (modifier) (of a transistor) having two terminals on the base or gate to improve the performance at high frequencies
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
tetrode in Science

tetrode

[tĕt′rōd′]
  1. A four-element electron tube containing an anode, cathode, control grid, and additional electrode called the screen. They function in the same manner as triode, but are more effective at higher frequencies due to the effect of the screen. See more at screen. See also pentode.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.