A compact folding knife. / The front-dive pike, in which the body folds and unfolds. / (colloquial) A semi-trailer truck accident in which the vehicle mimics the closing of a jack-knife.

To fold in the middle, as a jackknife does. / (colloquial) To cause a semi-trailer truck to fold like a jackknife in a traffic accident.

A physical exercise performed by jumping to a position with the legs spread wide and the hands touching overhead and then returning to a position with the feet together and the arms at the sides.

Alternative spelling of blackjack / Caranx lugubris, a gamefish / Bidens spp., from the family of Asteraceae / (obsolete) The larva of a turnip sawfly (Athalia rosae) / (mining, mineralogy) Sphalerite.

Alternative spelling of crackerjack

Children’s toy consisting of a small box from which a male figure pops out unexpectedly after some turnings of a crank.

a public executioner / the gallows / death / the devil

Alternative spelling of hijack

(uncountable) The illness yellow fever. / (countable, nautical) A yellow flag used by ships as a warning of disease. / (countable) The fish Caranx bartholomaei.

(electricity) A type of audio connector.