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[myoo-on] /ˈmyu ɒn/
noun, Physics.
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. Symbol: μ.
Origin of muon
1950-55; by shortening of mu meson; see mu, -on1
Related forms
muonic, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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Examples from the Web for muon
Historical Examples
  • That is, if the muon did not exist, what effect would this have on the structure of matter?

    LRL Accelerators Lawrence Radiation Laboratory
  • The behavior of the muon is well understood, but its role as one of the elementary particles is unknown.

    LRL Accelerators Lawrence Radiation Laboratory
  • The muon is unstable, eventually undergoing a radioactive decay into an electron.

    LRL Accelerators Lawrence Radiation Laboratory
  • Although the muon does not experience nuclear forces, it can interact weakly with nuclei.

    LRL Accelerators Lawrence Radiation Laboratory
British Dictionary definitions for muon


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
Derived Forms
muonic (mjuːˈɒnɪk) adjective
Word Origin
C20: short for mu meson
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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muon in Science
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. See Table at subatomic particle.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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