noun

jackknife

jackknife, clasp-knife, pocketknife

He always carries a jackknife in his pocket.

He always carries a jackknife in his pocket.

The truck did a jackknife on the icy road.

The lorry jack-knifed on the icy road.

((a/one's)) jackknife a folding knife He carries a jackknife in his pocket.

pocketknife, penknife, clasp-knife

From 'jack' (a common man's name, often used for tools) + 'knife'. Essentially, a common man's knife.

Imagine a man named Jack who always carries this type of folding knife for various tasks.

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