Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
the branch of electronics having to do with the focusing and deflection of beams of electrons by means of electric and magnetic fields, which act upon the beams in the same way that lenses act on light rays
Used by arrangement with John Wiley & Sons, Inc.
noun (used with a sing. verb)The 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.
The science of the control of electron motion by electron lenses in systems or under conditions analogous to those involving or affecting visible light.