Scrabble?! KNUCKLE

Definitions of KNUCKLE in various dictionaries:

noun - a joint of a finger when the fist is closed

verb - press or rub with the knuckles

verb - shoot a marble while keeping one's knuckles on the ground

Anatomy.

The prominence of the dorsal aspect of a joint of a finger, especially of one of the joints connecting the fingers to the hand.

A rounded protuberance formed by the bones in a joint.

A cut of meat centering on the carpal or tarsal joint, as of a pig.

The part of a hinge through which the pin passes.

To press, rub, or hit with the knuckles.

To shoot (a marble) with the thumb over the bent forefinger.

verb - to hit with the knuckles (the joints of the fingers)