[thurm-ahy-uh n, -on; thur-mee-uh n]
an ion emitted by incandescent material.
Origin of thermion
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for thermionic
Historical Examples of thermionic
of, relating to, or operated by electrons emitted from materials at high temperaturesa thermionic valve
physics an electron or ion emitted by a body at high temperature
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
An electrically charged particle or ion that is emitted by a heated conducting material. The electrons emitted from the cathodes of electron tubes (such as cathode ray tubes) are thermions.
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