Meaning of knuckle

knuck•le

1. a joint of a finger, esp. one of the articulations of a metacarpal with a phalanx.
2. the rounded prominence of such a joint when the finger is bent.
3. a joint of meat, consisting of the parts about the carpal or tarsal joint of a quadruped.
4. an angle or protrusion at the intersection of two members or surfaces, as in the timbers of a ship or in a roof.
5. See
6. a cylindrical projecting part on a hinge, through which an axis or pin passes; the joint of a hinge.
7. (in a wire mesh) a bend in a wire crossing another wire.
8. (on a chair arm) one of the ridges left at the front end by longitudinal flutes carved to accommodate the fingers.
9. a pronounced edge formed by a change in the form of the shell of a hull.

1. to rub or press with the knuckles.
2. to shoot (a marble) from the thumb and forefinger.
3. Just knuckle down for an hour or so and finish the work.
1. to apply oneself vigorously and earnestly; become serious:Just knuckle down for an hour or so and finish the work.
2. Also,knuckle under.to submit; yield.