muon

American  

[myoo-on] / ˈmyu ɒn /

noun

Physics.

1. a lepton similar in most respects to the electron except that it is unstable, it may be positively charged, and its mass is approximately 207 times greater; the positively charged muon is the antiparticle of the negatively charged muon. μ

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muon British  

/ ˈmjuːɒn, mjuːˈɒnɪk /

noun

1. a positive or negative elementary particle with a mass 207 times that of an electron and spin 1/ 2 . It was originally called the mu meson but is now classified as a lepton

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muon Scientific  

/ myo̅o̅′ŏn′ /

1. An elementary particle in the lepton family having a mass 209 times that of the electron, a negative electric charge, and a mean lifetime of 2.2 × 10 ^{- 6} seconds. The muon was originally called the mu-meson and was once thought to be a meson.

2. See Table at subatomic particle

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Other Word Forms

• muonic
  adjective

Etymology

Origin of muon

1950–55; by shortening of mu meson; see mu, -on ¹

Example Sentences

Neutrinos exist in three varieties, or "flavors," known as electron, muon, and tau.

From Science Daily • Mar. 3, 2026

Scientists realized that neutrinos come in three forms, known as electron, muon, and tau flavors, and that these flavors can change as neutrinos move through space.

From Science Daily • Jan. 12, 2026

According to the Standard Model, which is the leading framework in particle physics, there are three known types of neutrinos: electron, muon and tau.

From Science Daily • Dec. 18, 2025

A muon collider could be much smaller and cheaper than a functionally equivalent proton collider, advocates say.

From Science Magazine • Mar. 27, 2024

The world's ultimate pragmatist just shrugs and says: "NhUng gi minh mong it khi nao no jcay ra. Nhung gi minh khong muon thi no lai cti den."

From "Counting by 7s" by Holly Goldberg Sloan