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Science & TechnologyGreekEnglish

Thermionic

/ˌθɜːrmiˈɒnɪk/adjective

Relating to the emission of electrons from a heated surface, as in a vacuum tube.

The Greek roots

θέρμη
thérmē
heat
+
ἰόν
ión
going

Literally: heat-going

The story of the word

Faraday named the ion in 1834 on Whewell's advice, taking the neuter participle of ἰέναι, to go, because the thing went through the solution. Owen Richardson attached heat to it around 1909 for the electrons boiling off a hot filament, and won the 1928 Nobel Prize in Physics for the law that governs them. Every valve radio, every cathode ray tube and every early computer ran on that glow.

How it travelled
Ancient Greek → scientific coinage → English
First recorded
early 20th century

Same family

ionthermometerthermalanioncation

In a sentence

The museum keeps one thermionic valve lit so visitors can see the filament.

Built on the same root

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