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Jackknife - Meaning, Definition & English Examples

A jackknife is a small folding knife with a blade that pivots into the handle. It is also a diving position where the body bends at the waist and then straightens.

jackknife

/ˈdʒækˌnaɪf/ /ˈdʒæknaɪf/

Definition:

A folding pocketknife, or a dive where the body bends at the waist and then straightens.

Synonyms:

pocketknife, clasp knife, penknife

Part of Speech:

noun, verb

Antonyms:

straighten, unfold

Common Collocations:

jackknife dive, jackknife position, jackknife truck

Derivatives:

jackknifed, jackknifing

Usage Tips:

Use "jackknife" as a noun for the knife or dive; as a verb for bending sharply (e.g., a truck trailer).

Common Phrases:

jackknife into the pool, jackknifed trailer, sharp as a jackknife

Etymology:

Originates from "Jack" (generic name) + "knife," referring to its common use and folding mechanism.

Examples:

  • 1. He pulled out a jackknife to cut the rope.
  • 2. The diver performed a perfect jackknife off the high board.
  • 3. The truck's trailer jackknifed on the icy road.
  • 4. She keeps a small jackknife in her backpack for camping trips.

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