noun, plural jack·knives.
verb (used without object), jack·knifed, jack·knif·ing.
verb (used with object), jack·knifed, jack·knif·ing.
Examples from the Web for jackknife
"Wimmen are kind by natur," said the sailor, shutting his jackknife with a jerk, the only sign of impatience yet visible.Silent Struggles|Ann S. Stephens
Them natives'll give ye a silver fox fer a jackknife an' a barrel o' flour, an' a marten fer a gallon o' molasses.Ungava Bob|Dillon Wallace
Them are his trousers I've on me and he gave me an oilskin and that jackknife.Ulysses|James Joyce
And pray who shall search the vitals of a whale with a bodkin—who may reach his jackknife through the superposed bubber?The Fiend's Delight|Dod Grile
The knees of Elliot doubled up under him like the blade of a jackknife.The Yukon Trail|William MacLeod Raine