elbow joint vs hinge joint

elbow joint and hinge joint both are nouns.

Word	Noun	Adjective	Verb	Adverb
elbow joint	Yes	No	No	No
hinge joint	Yes	No	No	No

As nouns, hinge joint is a hypernym of elbow joint; that is, hinge joint is a word with a broader meaning than elbow joint:

elbow joint: hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped
hinge joint: a freely moving joint in which the bones are so articulated as to allow extensive movement in one plane

Other hypernyms of elbow joint include ginglymoid joint, ginglymus.

elbow joint (noun)	hinge joint (noun)
hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped	a joint allowing movement in one plane only
	a freely moving joint in which the bones are so articulated as to allow extensive movement in one plane