fermion
/ˈfɜːmɪɒn/
"fermion" is a 7-letter English headword indexed on PlainSpell.
The verdict
“fermion” is an uncommon English word, ranked #89,356 in English word frequency and used as a noun.
- #89,356
- frequency rank, English
- 7
- letters
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Any elementary or composite particle that has half-integer spin and thus obeys Fermi–Dirac statistics and the Pauli exclusion principle (equivalently, a particle for which the wavefunction of any s...
| Property | Value |
|---|---|
| Headword | fermion |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈfɜːmɪɒn/ |
| Letters | 7 |
| Frequency rank | #89,356 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “fermion” sits in English frequency
Spelling & Dictionary Insight
The English entry for fermion is 7 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ˈfɜːmɪɒn/. Corpus data places it at rank #89,356 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 2 distinct senses for this headword, so context determines which meaning a reader should apply.
Zero misspellings are on record for fermion in our index, typically a sign the spelling maps closely to how the word sounds. This headword has no recorded confusable partner, suggesting its spelling stands apart enough that readers rarely confuse it with something else.
Etymologically, the entry records: From Fermi + -on. Named after Italian-American physicist Enrico Fermi. Coined by English physicist Paul Dirac in 1945 in a lecture titled "Developments in Atomic Theory". The correct English form is fermion, spelled F-E-R-M-I-O-N.
Definition
- 1Any elementary or composite particle that has half-integer spin and thus obeys Fermi–Dirac statistics and the Pauli exclusion principle (equivalently, a particle for which the wavefunction of any system of identical such particles changes sign whenever two are swapped); a baryon, a lepton or a quark;
- 2Any elementary or composite particle that has half-integer spin and thus obeys Fermi–Dirac statistics and the Pauli exclusion principle (equivalently, a particle for which the wavefunction of any system of identical such particles changes sign whenever two are swapped); a baryon, a lepton or a quark; (slightly more loosely) any such particle or any composite particle composed of fermions.
Etymology
From Fermi + -on. Named after Italian-American physicist Enrico Fermi. Coined by English physicist Paul Dirac in 1945 in a lecture titled "Developments in Atomic Theory".
Synonyms
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
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Using “fermion”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is F-E-R-M-I-O-N - every other letter order is a misspelling in standard orthography.
- Say it as /ˈfɜːmɪɒn/ (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
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.