knuckle joint knuckle guard • knuckle-joint press · · · Info · Definitions · Synonyms · Characters · · knuckle joint · · Text Common · · Latin · · Scripts 13 · · Length Definitions · · · (noun) a joint of a finger when the fist is closed. Synonyms: knuckle, metacarpophalangeal joint. · · Noun Definition 1 (noun) a joint allowing movement in one plane only. Synonyms: hinge joint. · · Noun Definition 2 Synonyms · · · knuckle · · Synonym 1 metacarpophalangeal joint · · Synonym 2 Characters · · space U+0020 c latin small letter c U+0063 e latin small letter e U+0065 i latin small letter i U+0069 j latin small letter j U+006A k latin small letter k U+006B l latin small letter l U+006C n latin small letter n U+006E o latin small letter o U+006F t latin small letter t U+0074 u latin small letter u U+0075