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
From the M-W Editors
Recent Examples of jackknife from the Web
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Meanwhile, deadbugs, jackknives, ab-wheel rollouts, and boat pose variations will hit both portions.
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One photograph captured the image of a towheaded boy of about 3, stripping bark off a stick with a jackknife.
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T. Christianson (@MSPPIO_SOUTH) January 10, 2017 SE MN very windy and fresh snow cause semis to jackknife.
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
jackknife
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
The truck jackknifed on the icy road.
First Known Use of jackknife
1806
JACKKNIFE Defined for English Language Learners
jackknife
playDefinition of jackknife for English Language Learners
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: a small knife that has a folding blade
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: a dive in which you bend from the waist and touch your ankles and then straighten out
jackknife
Definition of jackknife for English Language Learners
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: 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
Definition of jackknife for Students
jackknives
\-ˌnīvz\: a knife that has a folding blade or blades and can be put in a pocket
Definition of jackknife for Students
jackknifed
;jackknifing
: to double up like a jackknife
Learn More about jackknife
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See words that rhyme with jackknife Spanish Central: Translation of jackknife Nglish: Translation of jackknife for Spanish speakers Britannica English: Translation of jackknife for Arabic speakers
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