noun, plural jack·knives.
verb (used without object), jack·knifed, jack·knif·ing.
verb (used with object), jack·knifed, jack·knif·ing.
Origin of jackknife
Examples from the Web for jack-knife
Historical Examples of jack-knife
Kit bought one of these for a jack-knife,—for a curiosity, of course.Left on Labrador
Charles Asbury Stephens
Quin, doubled up like a jack-knife beside her, was drunk with ecstasy.Quin
Alice Hegan Rice
Yes, there was the cache I had made by splitting the pasteboard with my jack-knife.The Plum Tree
David Graham Phillips
Then with his jack-knife he proceeded to investigate the inside.Tabitha's Vacation
Ruth Alberta Brown
He had left his half-axe in camp, and when he felt in his pocket for his jack-knife it was not there.Forest Neighbors
William Davenport Hulbert
noun plural -knives
also jackknife, large pocket knife, 1711, probably American English, "perh[aps] associated with some sense of JACK sb.1, but cf. jackleg knife" [OED]; see jack + knife (n.). Jackleg was a U.S. colloquial term of contempt from c.1850. On another theory, so called because it originally was associated with sailors. As a kind of swimming dive, from 1922. As a type of tractor-trailer accident, 1966. Both from the notion of folding, as the knife does.
1776, "to stab," from jack-knife (n.). Intransitive meaning "to fold or bend" the body is said to date from the time of the American Civil War. The truck accident verbal sense is from 1949. Related: Jackknifed; jackknifing.