jackknife

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jackknife

1. a knife with the blade pivoted to fold into a recess in the handle
2. a former name for a type of dive in which the diver bends at the waist in midair, with his legs straight and his hands touching his feet, finally straightening out and entering the water headfirst: forward pike dive
References in periodicals archive ?
The STS-ACS helps prevent accidents involving jackknifing, trailer swing and rollover by mechanically limiting the degree of rotation of the tractor relative to the trailer.
The STS technology prevents tractor-trailers from losing control and jackknifing by inserting a high tensile steel mechanical limiter between the forks of the fifth wheel.
Twenty-three percent of all large truck accidents are caused by out-of-control catastrophes such as trailers swinging sideways on public roads, rigs rolling over spilling hazardous cargo, or jackknifing, according to the U.
The third component of the life-saving Lanescan(TM) system, Lanescan III, is the Jackknife Warning Alarm, which gives drivers early warning when their trucks are jackknifing.