1. (noun)
knuckle, knuckle joint, metacarpophalangeal joint
- a joint of a finger when the fist is closed Synonyms: metacarpophalangeal joint, knucklejoint, hingejoint, knuckle
2. (noun)
knuckle joint, hinge joint
- a joint allowing movement in one plane only Synonyms: ginglymoid joint, metacarpophalangeal joint, ginglymus, knuckle joint, hingejoint, knuckle