jackknife
noun
Definitions
A compact folding knife.
Example: He kept a jack-knife in his pocket for various tasks.
The front-dive pike, in which the body folds and unfolds.
Example: It took me hundreds of dives to master even the simple jackknife
A semi-trailer truck accident in which the vehicle mimics the closing of a jack-knife.
Example: I have seen several jack-knives along that dangerous stretch of road.
verb
Definitions
To fold in the middle, as a jackknife does.
Example: The cat jackknifed in the air and landed gracefully on its feet.
To cause a semi-trailer truck to fold like a jackknife in a traffic accident.
Example: Before I knew what was happening, I'd jack-knifed the truck.
noun
Definitions
A resampling method that applies estimators to all subsamples that each omit a single different group (possibly of a single datapoint) of the original sample to provide a sample distribution of the estimate.