elbow joint has 5 distinct synonyms spread across 1 of its 1 sense. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped
Synonyms, antonyms and the broader and narrower relations for elbow joint come from Princeton University’s WordNet. Full sources and licences.