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Glite Dictionary
jack-knife

jack-knife

7.0
A large pocket knife with a blade that folds and locks
  • noun
  • /ˈdʒækˌnaɪf/
translation icon : navaja
  • The farmer stood, reached into a coverall pocket, and took out a bone-handled jack-knife.

Examples

  • He always carries a jack-knife in his pocket for everyday tasks.

  • The hiker used a jack-knife to prepare food during their camping trip.

  • With his trusty jack-knife, he easily whittled the wood into a smooth shape.

Synonyms

jackknife
vsjack-knife
  • US
1 7.6

A small folding knife with blades that fold into its handle

is a pocket folding knife that also locks its blade into position
clasp knife
vsjack-knife
  • Archaic
1 6.4

A large folding knife with blades that fold into the handle

is the version that specifies a locking blade rather than only folding

How Small

parer
7.4
jack-knife
7.0
cleaver
28 3.5

Surface Forms

jack-knife singular
jack-knives plural

Morphology

jack-knife = jack + knife (transparent) = jack + knife

The meaning is directly built from 'jack' + 'knife' to indicate a specific type of knife (a folding pocketknife), so learners knowing the components can infer the sense.

Etymology

Jack-knife comes from jack, an old nickname for a common man or a simple tool that suggests 'ordinary' or 'useful', plus knife, so imagine a small, handy knife anyone might carry. That's why a jack-knife means a folding pocketknife you can fold up and lock for safe use.