A
pocketknife is a foldable
knife with one or more
blades that fit inside the handle that can still fit in a
pocket. It is also known as a
jackknife or
jack-knife. A typical blade length is . Pocket knives are versatile tools, and may be used for anything from opening an
envelope, to cutting
twine, slicing a piece of
fruit or even as a means of
self-defense.