ax·​ion | \ ˈak-sē-(ˌ)än How to pronounce axion (audio) \

Definition of axion

: a hypothetical subatomic particle of low mass and energy that is postulated to exist because of certain properties of the strong force

Examples of axion in a Sentence

Recent Examples on the Web As the old axion goes, measure twice (or even three times!) and cut once. Hadley Keller, House Beautiful, "Your Expert Guide to Hanging Wallpaper," 29 May 2020 Live Science shared the XENON collaboration’s press release with two axion experts. Rafi Letzter, Scientific American, "Physicists Announce Potential Dark Matter Breakthrough," 17 June 2020 This is the shape of the mathematical function defining the axion field. Quanta Magazine, "Axions Would Solve Another Major Problem in Physics," 17 Mar. 2020 The new idea, which goes by the name axiogenesis, could further motivate experimental searches for the axion. Quanta Magazine, "Axions Would Solve Another Major Problem in Physics," 17 Mar. 2020 To demonstrate their idea, Jiang and Wilczek focused on an unorthodox set of rules called axion electrodynamics, which could give rise to unique properties. Quanta Magazine, "‘Quantum Atmospheres’ May Reveal Secrets of Matter," 25 Sep. 2018 Wilczek came up with the theory in 1987 to describe how a hypothetical particle called an axion would interact with electricity and magnetism. Quanta Magazine, "‘Quantum Atmospheres’ May Reveal Secrets of Matter," 25 Sep. 2018 Enter the axion, the second-most promising candidate for dark matter. Jennifer Ouellette, Ars Technica, "Physicists propose listening for dark matter with plasma-based “axion radio”," 17 Oct. 2019 Then there are theorized particles like SIMPs and axions—and countless other potential clues. Joe Lindsey, Popular Mechanics, "Filling the Void: What Is Dark Matter?," 28 May 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'axion.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of axion

1978, in the meaning defined above

History and Etymology for axion

axi(al) + -on entry 2

Note: The name axion was introduced by the American physicist Stephen Weinberg (born 1933) in "A New Light Boson?", Physical Review Letters, vol. 40, no. 4 (January 23, 1978), p. 233; and by American physicist Frank Wilczek (born 1951) in "Problems of Strong P and T Invariance in the Presence of Instantons," Physical Review Letters, vol. 40, no. 5, p. 279. In an article in the on-line journal Quanta, "Time's (Almost) Irreversible Arrow" (January 7, 2016), Frank Wilczek explained the coinage as follows: "A few years before [in 1977], a supermarket display of brightly colored boxes of a laundry detergent named Axion had caught my eye. It occurred to me that 'axion' sounded like the name of a particle and really ought to be one. So when I noticed a new particle that 'cleaned up' a problem with an 'axial' current, I saw my chance. (I soon learned that Steven Weinberg had also noticed this particle, independently. He had been calling it the 'Higglet.' He graciously, and I think wisely, agreed to abandon that name.) Thus began a saga whose conclusion remains to be written."

Keep scrolling for more

Learn More about axion

Time Traveler for axion

Time Traveler

The first known use of axion was in 1978

See more words from the same year

Statistics for axion

Cite this Entry

“Axion.” Dictionary, Merriam-Webster, Accessed 22 Jan. 2021.

Comments on axion

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


Test Your Vocabulary

Slippery Words Quiz—Changing with the Times

  • ducreux self portrait yawning
  • What is an earlier meaning of nice?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

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