different between penknife vs jackknife

English

Etymology

From Middle English penne knyfe; equivalent to pen +? knife

Noun

penknife (plural penknives)

1. Originally a small utility knife for cutting the points of quill feathers or reeds into nibs to provide or repair writing implements in times before pens with artificial nibs, generally metal, became commercially available in the 19th century. Early versions of penknives commonly were small sheath knives.
2. A small knife designed for safe and convenient storage, typically in the form of a miniature clasp knife, or with blade retractable into the handle. For the most part, such more convenient designs eventually replaced rigid pen knives in cutting quill pens or sharpening pencils.
3. As the need to cut nibs for pens fell away, but small utility pocket-knives remained popular, "penknife" became synonymous with "pocket-knife". Modern penknives often incorporate other tools such as corkscrews, but as a rule are smaller than general-purpose pocketknives.

See also

• clasp knife
• jackknife
• pocketknife
• Swiss Army knife

Translations

Middle English

Noun

penknife

1. Alternative form of penne knyfe

English

Noun

jackknife (plural jackknives)

1. Alternative spelling of jack-knife
   • 1887, Julian Hawthorne, A Tragic Mystery: From the Diary of Inspector Byrnes (page 25)

     […] 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.

2. (statistics) A 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.

Synonyms

• (statistics): leave-one-out

Translations

See also

• Resampling (statistics) on Wikipedia.Wikipedia

Verb

jackknife (third-person singular simple present jackknifes, present participle jackknifing, simple past and past participle jackknifed)

1. Alternative spelling of jack-knife