Noun: jackknife (jackknives) 'jak,nIf
- A large knife with one or more folding blades
"He pulled out his jackknife to cut the rope";
- clasp knife
- A dive in which the diver bends to touch the ankles before straightening out
"His jackknife dive impressed the judges"
- (sport) dive into the water bending the body at the waist at a right angle, like a jackknife
"The diver jackknifed off the high board"
Derived forms: jackknives, jackknifing, jackknifed, jackknifes
Type of: dive, pocket knife, pocketknife
Encyclopedia: Jackknife