knuckle joint knuck·le·joint uncommon noun 1. a joint of a finger when the fist is closed Synonymsknuckleknuckle jointmetacarpophalangeal joint 2. a joint allowing movement in one plane only Synonymsknuckle jointhinge joint Related words Word family knuckle Broader terms jointsynovial joint Parts finger WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
