jack-knife
verb1
To fold in the middle, as a jackknife does.
- The cat jackknifed in the air and landed gracefully on its feet.
- There was a world inside that tall grass. You could plop yourself down in the middle of it with the scraggly stems against the back of your neck and the endless grasses rising up and jackknifing against the bigbluesky, and the ranch and all of its players would fade into a distant dream.2009, Reif Larsen, The Selected Works of T.S. Spivet, Pinguin Books, page 37:
1 more example
- Ten of the freight train's wagons had derailed, two of them foul of the Down Fast. At 2308, the TPO struck one of them, causing the locomotive (86239) to jack-knife and turn so that it was almost touching the end wall of a house in The Russetts, a new-build row that sat close to the line.2026 March 18, Greg Morse, “1996 crash driving freight reforms”, in RAIL, number 1057, page 50:
2
Colloquial To cause a semi-trailer truck to fold like a jackknife in a traffic accident.
- Before I knew what was happening, I'd jack-knifed the truck.
- Before I knew what was happening, I'd jack-knifed.