knuckle

/ˈnʌkəl/

/ˈnʌkəl/

Other forms: knuckles; knuckled; knuckling

Your knuckles are the joints in your fingers that are farthest from your fingernails. When you clench your hand into a fist, your knuckles are especially prominent.

A knuckle is the part of your hand that makes it possible to move a finger freely, and if someone offers you a "knuckle sandwich," you should politely decline, since they're actually planning to make a fist and punch you in the mouth. To knuckle is to rub with the knuckles, like when you knuckle a bit of sand out of your eye. The root of knuckle is the Proto-Germanic knuk-, "bone."

Definitions of knuckle

1. noun

   a joint of a finger when the fist is closed
   synonyms: knuckle joint, metacarpophalangeal joint

   type of:

   articulatio synovialis, diarthrosis, synovial joint

   a joint so articulated as to move freely
2. verb

   press or rub with the knuckles
   type of:

   press

   exert pressure or force to or upon
3. verb

   shoot a marble while keeping one's knuckles on the ground
   type of:

   shoot

   throw or propel in a specific direction or towards a specific objective