muon

/ˈmjuːɒn/

//ˈmjuːɒn// noun

"muon" is a 4-letter English headword indexed on PlainSpell.

The verdict

“muon” is uncommon English (frequency #61,653 among 36,575 “M” headwords), classed as a noun. The kind of spelling people second-guess.

#61,653
frequency rank, English
36,575
“M” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - An unstable elementary particle in the lepton family, having similar properties to the electron but with a mass 207 times greater.

Key facts for muon
PropertyValue
Headwordmuon
LanguageEnglish
Part of speechNoun
IPA/ˈmjuːɒn/
Letters4
Frequency rank#61,653
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “muon” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). muon lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Rare enough to double-check

muon is uncommon English at frequency #61,653 among 36,575 “M” headwords, classed as anoun, transcribed /ˈmjuːɒn/. Rarity is why readers land here mid-draft. Gloss: "An unstable elementary particle in the lepton family, having similar properties to the electron but with a mass 207 times greater.".

Our edit-distance generator produced no likely misspellings for muon, suggesting the orthography follows predictable English patterns. It is not paired with a close-neighbour confusable in our dataset, which tends to mean the word is visually distinctive enough to stand on its own.

Etymologically, the entry records: 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. The correct English form is muon, spelled M-U-O-N.

Definition

  1. 1
    An unstable elementary particle in the lepton family, having similar properties to the electron but with a mass 207 times greater.

Etymology

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.

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "muon"?
"muon" is spelled M-U-O-N. The IPA pronunciation is /ˈmjuːɒn/.
What does "muon" mean?
As a noun, "muon" means: An unstable elementary particle in the lepton family, having similar properties to the electron but with a mass 207 times greater.
How do you pronounce "muon"?
The IPA (International Phonetic Alphabet) transcription for "muon" is /ˈmjuːɒn/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "muon"?
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. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “muon”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is M-U-O-N - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈmjuːɒn/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Browse more English words and confusable pairs in the same reference. English words

Other uncommon English words near this rank

Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list