The story
Contraction of the earlier term mu-meson; the particle has now been recategorised as a lepton. Coined by Italian physicist Enrico Fermi in 1951 in his book Elementary Particles.
Etymology from Wiktionary, CC BY-SA 4.0.
muon
Today it means: An unstable elementary particle in the lepton family, having similar properties to the electron but with a mass 207 times greater. Full definition →