mu·​on | \ ˈmyü-ˌän How to pronounce muon (audio) \

Definition of muon

: an unstable lepton that is common in the cosmic radiation near the earth's surface, has a mass about 207 times the mass of the electron, and exists in negative and positive forms

Other Words from muon

muonic \ myü-​ˈä-​nik How to pronounce muon (audio) \ adjective

Examples of muon in a Sentence

Recent Examples on the Web In particular, Kotwal and his colleagues sought out collisions that produced two specific pairs of particles: either a muon and a neutrino, or an electron and a neutrino. Jennifer Leman, Popular Mechanics, 7 Apr. 2022 This is because the rules of quantum mechanics are not consistent with the simplest kind of new force unless that force affects at least one other kind of particle besides the muon. Scientific American, 1 Feb. 2022 The endless muon rainstorm will shower the volcano at an angle. New York Times, 10 Nov. 2021 But this April, physicists announced the first results of an experiment designed specifically to chase just such an anomaly, one involving the intrinsic magnetism of a particle called the muon. Michael Moyer, Quanta Magazine, 22 Dec. 2021 Although the phenomenon of neutrino oscillation had not yet been definitively demonstrated, several earlier measurements suggested how quickly muon type neutrinos should oscillate into the other two varieties. Don Lincoln, Forbes, 27 Oct. 2021 Both sets of results involve the strange, fleeting particle called the muon. Seth Borenstein, USA TODAY, 8 Apr. 2021 Several groups have also applied the lattice to the muon’s magnetism, albeit with sizable uncertainties. Adrian Cho, Science | AAAS, 14 Apr. 2021 In 1936, Anderson and his student, Seth Neddermeyer, recreated it in the lab, revealing the nature of the muon for the first time. Ethan Siegel, Forbes, 10 Sep. 2021 See More

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

First Known Use of muon

1951, in the meaning defined above

History and Etymology for muon

contraction of earlier mu-meson, from mu

Learn More About muon

Dictionary Entries Near muon

Muntz metal



See More Nearby Entries 

Statistics for muon

Last Updated

17 Apr 2022

Cite this Entry

“Muon.” Dictionary, Merriam-Webster, Accessed 29 May. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More from Merriam-Webster on muon Encyclopedia article about muon


Test Your Vocabulary

Which Word Does Not Belong?

  • one green toy robot amidst many red toy robots
  • Which of these words does not mean "nonsense"?
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!