1

jackknife

noun jack·knife \ ˈjak-ˌnīf \

Definition of jackknife

1 : a large strong pocketknife
2 : a dive executed headfirst in which the diver bends from the waist and touches the ankles while holding the knees unbent and then straightens out

Recent Examples of jackknife from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'jackknife.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of jackknife

1711


2

jackknife

verb

Definition of jackknife

intransitive verb
1 : to double up like a jackknife
  • jackknifed into a seat beside me, folding up his six feet eight
  • —Lady Bird Johnson
2 : to turn and form an angle of 90 degrees or less with each other used especially of a tractor-trailer combination
transitive verb
1 : to cause to double up like a jackknife
2 : to cut with a jackknife

Examples of jackknife in a Sentence

  1. The truck jackknifed on the icy road.

Recent Examples of jackknife from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'jackknife.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of jackknife

1806


JACKKNIFE Defined for English Language Learners

jackknife

noun

Definition of jackknife for English Language Learners

  • : a small knife that has a folding blade

  • : a dive in which you bend from the waist and touch your ankles and then straighten out


jackknife

verb

Definition of jackknife for English Language Learners

  • : to bend in the middle like a folding jackknife; especially of a large truck : to have the back part slide out of control toward the front part


JACKKNIFE Defined for Kids

1

jackknife

noun jack·knife \ ˈjak-ˌnīf \

Definition of jackknife for Students

plural jackknives \-ˌnīvz\
: a knife that has a folding blade or blades and can be put in a pocket

2

jackknife

verb

Definition of jackknife for Students

jackknifed; jackknifing
: to double up like a jackknife


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