n.
1.a large knife with one or more folding blades
2.a dive in which the diver bends to touch the ankles before straightening out jackknife v.
1.dive into the water bending the body at the waist at a right angle, like a jackknife
Idiom of the Day
make a dent in (something)
to make progress doing something
We worked hard all day but we did not make a dent in the amount of work that we had to do.