sb. [app. of U.S. origin: perh. associated with some sense of JACK sb.1, but cf. jackleg knife s.v. JOCKTELEG.]
1. A large clasp-knife for the pocket: see also quot. 1867.
1776. Militia Act, New Hampsh., in Outing (1895), XXVII. 80/1. A hundred buckshot, a jack-knife and tow for wadding, six flints, one pound of powder.
1825. J. Neal, Bro. Jonathan, II. 227. Ever there [Jerusalem]?—I was—got a jacknife, that Mr. Titus—emperor Titus—you know—he lost it, one afternoon.
1861. Dickens, Gt. Expect., xl. Taking out his great horn-handled jack-knife … and cutting his food.
1867. Smyth, Sailor’s Word-bk., Jack-knife, a horn-handled clasp-knife with a laniard, worn by seamen.
1870. Emerson, Soc. & Solit., Work & Days, Wks. (Bohn), III. 69. The old school-house, and its porch, somewhat hacked by jack-knives.
2. In a telephone station: = JACK sb.1 15 d.
Hence Jack-knife v., (a) trans. to cut with a jack-knife; (b) intr. to double up like a jack-knife.
1855. Boyd, Oakw. Old, I. The stage-yankee’s method of recording things, in jackknifed notches on a softwood stick.
1889. Amer. Ann. Deaf, Oct., 277. Desks ink-stained and jack-knifed like those of a country school.
1897. H. Porter, Campaigning with Grant, ix. 141. One of their amusements in camp … was to throw stones and chips past one another’s heads, and raise a laugh at the active dodging and bending the body low or ‘jack-knifing’ as the men called it.
