jackknife
"jackknife" is a 9-letter English headword indexed on PlainSpell.
The verdict
“jackknife” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.
- Unranked
- below top-frequency English
- 9
- letters
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Alternative spelling of jack-knife.
Corpus desk
Index EN-jackknife · jackknife · English
jackknife · unranked · 0 variants · 0 confusables
- FREQ-UNRANKED Unranked
- LEN-LONG 9 letters
- VOW-3 3 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-THIN "J" thin
- PHOTO-UNK Peer pending
Read with this headword: Spelling guide for this pattern
Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.
| Property | Value |
|---|---|
| Headword | jackknife |
| Language | English |
| Part of speech | Noun |
| Letters | 9 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “jackknife” in English
Rare enough to double-check
jackknife is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. 2 senses are on record.
We couldn't generate a plausible misspelling set for jackknife, since its letter sequence doesn't invite the usual edit-distance slips. No close-neighbour confusable shows up for this headword in our dataset, a sign it's visually distinctive enough not to be mixed up with another word.
Our source data has no etymology on file for this entry, so its spelling pattern is best understood through pronunciation rather than a traceable origin. The correct English form is jackknife, spelled J-A-C-K-K-N-I-F-E.
Definition
- 1Alternative spelling of jack-knife.
- 2A resampling method that applies estimators to all subsamples that each omit a single different group (possibly of a single datapoint) of the original sample to provide a sample distribution of the estimate.
Recorded use
Wiktionary exampleThese source excerpts show how jackknife appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
[…] near it is a cluster of weapons of villanous aspect, comprising every thing from a Malayan creese to a sailor's jackknife or a Smith & Wesson revolver.
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.