knuckle

The definition of knuckle is a joint at the hand or toe that sticks out when you make a fist.

(noun)

The joint in the middle of your finger that sticks forward when you make a fist is an example of the knuckle.

See knuckle in Webster's New World College Dictionary

noun

1. a joint of the finger; esp., the joint connecting a finger to the rest of the hand
2. the rounded knob formed by the bones at such a joint
the knee or hock joint and nearby parts of a pig or other animal, used as food
something resembling a knuckle, as any of the projecting, cylindrical parts through which a pin is passed to form a hinge
☆ brass knuckles
Archit. the central joint in a gambrel or curb roof

Origin: ME knokyl < or akin to MDu & MLowG knokel, dim. of knoke, bone < IE *gneuĝ-: for IE base see knot

transitive verb knuckled, knuckling

to strike, press, or touch with the knuckles

See knuckle in American Heritage Dictionary 4

noun

a. The prominence of the dorsal aspect of a joint of a finger, especially of one of the joints connecting the fingers to the hand.
b. 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.
A sharp angle formed by the meeting of two surfaces, especially two ship's timbers.
knuckles Brass knuckles.

transitive verb knuck·led, knuck·ling, knuck·les