Noun knuckle has 1 sense
  1. knuckle, knuckle joint, metacarpophalangeal joint - a joint of a finger when the fist is closed
    --1 is a kind of synovial joint, articulatio synovialis, diarthrosis
    --1 is a part of finger
    Derived form: verb knuckle1
,Verb knuckle has 2 senses
  1. knuckle - press or rub with the knuckles
    --1 is one way to
    Derived form: noun knuckle1
    Sample sentence:
    Somebody ----s something
  2. knuckle - shoot a marble while keeping one's knuckles on the ground
    --2 is one way to
    Sample sentence:
    Somebody ----s