Definition of thermion in English:

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Pronunciation: /ˈTHərmˌēən/


An ion or electron emitted by a substance at high temperature.
Example sentences
  • Alloyed thorium enhances the emission of thermions by lowering the work function barriers.
  • When the main power supply of the X-ray tube is on, the cathode emits thermions as it is heated by a heater.
  • Another theory is that, since energy is required to extract electrons from the heated material, there should be cooling when thermions are emitted.


Early 20th century: from thermo- 'of heat' + ion.

For editors and proofreaders

Syllabification: therm·i·on

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