mu·​on | \ˈmyü-ˌän \

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

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Other Words from muon

muonic \ myü-​ˈä-​nik \ adjective

Examples of muon in a Sentence

Recent Examples on the Web

Travelling at close to the speed of light, muons shower Earth from all angles. Elizabeth Gibney, Scientific American, "Muons: The Little-known Particles Helping to Probe the Impenetrable," 28 May 2018 There are three types of antineutrino just as there are three types of regular neutrino—electron, muon, and tau. Avery Thompson, Popular Mechanics, "New Experiment Hints at Why the Universe Is Made of Something Rather Than Nothing," 8 Aug. 2016 The MiniBooNE experiment shoots a beam of muon neutrinos toward a giant oil tank. Natalie Wolchover, Washington Post, "Evidence for a new fundamental particle thrills and baffles physicists," 18 June 2018 This would give an additional path by which muon neutrinos produced in the decays could oscillate into electron neutrinos, having spent a short bit of time as sterile neutrinos in between. John Timmer, Ars Technica, "Weird neutrino excess won’t go away, hints at new physics," 8 June 2018 Neutrinos come in three types — muon neutrinos, tau neutrinos and electron neutrinos. NBC News, "This bold experiment aims to solve one of the biggest mysteries in science," 8 May 2018 With each collision that registers, DUNE scientists should be able to determine whether the neutrinos and antineutrinos have changed type — for example, from a muon neutrino to an electron neutrino. NBC News, "This bold experiment aims to solve one of the biggest mysteries in science," 8 May 2018 Using robotic probes and 3-D imaging with muons (a type of subatomic particle), workers have found pebbly deposits and debris at various areas inside the primary containment vessels in the three of the plant’s reactor units. Tim Hornyak, Scientific American, "Clearing the Radioactive Rubble Heap That Was Fukushima Daiichi, 7 Years On," 9 Mar. 2018 That's because it was found using muon radiography, a type of imaging that uses subatomic particles to peer through walls or solid structures. National Geographic, "Unsolved Science Mysteries From 2017," 18 Dec. 2017

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.

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First Known Use of muon

1951, in the meaning defined above

History and Etymology for muon

contraction of earlier mu-meson, from mu

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Dictionary Entries near muon



Muntz metal





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Last Updated

16 Oct 2018

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Time Traveler for muon

The first known use of muon was in 1951

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to express warning or disapproval

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