noun (used with a singular verb)
the study and use of the physical and optical properties of beams of electrons under the influence of electric or magnetic fields.
Origin of electron optics
First recorded in 1915–20
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
(functioning as singular) the study and use of beams of electrons and of their deflection and focusing by electric and magnetic fields
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