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English definition of “jackknife”

jackknife

noun [C]  /ˈdʒækˌnɑɪf/ us  

jackknife noun [C] (KNIFE)

a knife with one or more blades that fold into the handle, which fits into a person’s pocket

jackknife

verb [I]  /ˈdʒækˌnɑɪf/ us  

jackknife verb [I] (MAKE AN ANGLE)

to bend in half, or bend so the parts make a sharp angle: A truck jackknifed on Route 80 this morning.
(Definition of jackknife from the Cambridge Academic Content Dictionary © Cambridge University Press)
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