Definitions for: Jackknife

[n] a dive in which the diver bends to touch the ankles before straightening out
[n] a large knife with one or more folding blades
[v] dive into the water bending the body at the waist at a right angle, like a jackknife

Webster (1913) Definition: Jack"knife`, n.
A large, strong clasp knife for the pocket; a pocket knife.

Synonyms: clasp knife

See Also: dive, dive, diving, pocket knife, pocketknife