Definition of "jackknife"

jackknife

noun
plural jackknives
1. Alternative spelling of jack-knife
  Quotations
  […] 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.
  1887, Julian Hawthorne, A Tragic Mystery: From the Diary of Inspector Byrnes, page 25
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.
verb
third-person singular simple present jackknifes, present participle jackknifing, simple past and past participle jackknifed
1. Alternative spelling of jack-knife