jackknife

1. A compact folding knife.

   He kept a jack-knife in his pocket for various tasks.

2. The front-dive pike, in which the body folds and unfolds.

   It took me hundreds of dives to master even the simple jackknife

3. A semi-trailer truck accident in which the vehicle mimics the closing of a jack-knife.

   I have seen several jack-knives along that dangerous stretch of road.

1. To fold in the middle, as a jackknife does.

   The cat jackknifed in the air and landed gracefully on its feet.

2. 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.

noun

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.