femtometre
"femtometre" is a 10-letter English headword indexed on PlainSpell.
The verdict
“femtometre” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.
- Unranked
- below top-frequency English
- 10
- letters
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - An SI unit of length equal to 10⁻¹⁵ metres. Symbol: fm
| Property | Value |
|---|---|
| Headword | femtometre |
| Language | English |
| Part of speech | Noun |
| Letters | 10 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “femtometre” sits in English frequency
Rare enough to double-check
femtometre is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "An SI unit of length equal to 10⁻¹⁵ metres. Symbol: fm".
femtometre doesn't appear in our generated misspelling index, suggesting the orthography follows predictable English patterns. It is not paired with a close-neighbour confusable in our dataset, which typically means the spelling is too distinctive to be mistaken for another word.
Etymologically, the entry records: From femto- + metre. The correct English form is femtometre, spelled F-E-M-T-O-M-E-T-R-E.
Definition
- 1An SI unit of length equal to 10⁻¹⁵ metres. Symbol: fm
Etymology
From femto- + metre.
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). See the methodology for how each field is sourced and updated.
Frequently Asked Questions
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Using “femtometre”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is F-E-M-T-O-M-E-T-R-E - every other letter order is a misspelling in standard orthography.
- 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.