Merriam-Webster Logo
SINCE 1828
Menu
dictionary thesaurus

thermionic

adjective
therm·​ion·​ic | \ ˌthər-(ˌ)mī-ˈä-nik How to pronounce thermionic (audio) \

Definition of thermionic

: relating to, using, or being the emission of charged particles (such as electrons) by an incandescent material

First Known Use of thermionic

1909, in the meaning defined above

History and Etymology for thermionic

thermion charged particle from an incandescent source, from therm- + ion

Keep scrolling for more

Learn More about thermionic

Statistics for thermionic

Look-up Popularity

Time Traveler for thermionic

The first known use of thermionic was in 1909

See more words from the same year

More from Merriam-Webster on thermionic

Rhyming Dictionary: Words that rhyme with thermionic

Comments on thermionic

What made you want to look up thermionic? Please tell us where you read or heard it (including the quote, if possible).

Show Comments  Hide Comments 

WORD OF THE DAY

resurrection

Listen to the pronounciation of resurrection

an act or instance of returning to life

Get Word of the Day daily email!

Test Your Vocabulary

Words from Greek and Latin Quiz

  • roman forum
  • Which of the following months comes from a Latin word for “ten”?
True or False

Test your knowledge - and maybe learn something along the way.

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Words at Play
Ask the Editors
Word Games