fermi
/ˈfɜː(ɹ)mi/
"fermi" is a 5-letter English headword indexed on PlainSpell.
The verdict
“fermi” is a moderately-common English word, ranked #35,718 in English word frequency and used as a noun.
- #35,718
- frequency rank, English
- 5
- letters
- 7
- tracked misspellings
- 17
- confusable pairs
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - An obsolete name of the unit of length equal to one femtometre (10⁻¹⁵ m).
Visual similarity to commonly confused words
How many letter changes separate each confused pair (Levenshtein distance, normalized).
Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).
| Property | Value |
|---|---|
| Headword | fermi |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈfɜː(ɹ)mi/ |
| Letters | 5 |
| Frequency rank | #35,718 |
| Misspellings tracked | 7 |
| Confusable pairs | 17 |
| Source | Wiktionary (kaikki.org) |
Where “fermi” sits in English frequency
Spelling & Dictionary Insight
The English entry for fermi is 5 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ˈfɜː(ɹ)mi/. Corpus data places it at rank #35,718 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. The dominant gloss from Wiktionary reads: "An obsolete name of the unit of length equal to one femtometre (10⁻¹⁵ m).".
Our generated misspelling index lists 7 likely wrong-spelling variants for fermi, with forms such as "efrmi", "femri", and "ferim". Every one of these variants traces to a single-character edit -- an added or dropped letter, a swapped consonant, or a vowel swap -- the kind of slip a spell-checker is built to catch. It also participates in 17 confusable-pair relationships, "form", "firm", "fern", and more, since the words sound or look close enough that writers reach for the wrong one mid-sentence.
Etymologically, the entry records: Named after Italian physicist Enrico Fermi. The correct English form is fermi, spelled F-E-R-M-I.
Definition
- 1An obsolete name of the unit of length equal to one femtometre (10⁻¹⁵ m).
Etymology
Named after Italian physicist Enrico Fermi.
Common misspellings
Also misspelled as: efrmi,femri,ferim,fermmi,ferrmi,ffermi,fremi
Misspelling Pattern Breakdown
How far each generated variant is from the correct spelling of fermi - expressed in single-character edits (insert, delete, or swap one letter). Bigger bars stand out at a glance; a one-edit slip is the hardest to catch.
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 "fermi"?
What does "fermi" mean?
What words are commonly confused with "fermi"?
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Using “fermi”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is F-E-R-M-I - every other letter order is a misspelling in standard orthography.
- Say it as /ˈfɜː(ɹ)mi/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Don't mix it up with “form” - see the side-by-side comparison. fermi vs form
- 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.