human elbow vs ginglymus

human elbow and ginglymus both are nouns.

Word	Noun	Adjective	Verb	Adverb
human elbow	Yes	No	No	No
ginglymus	Yes	No	No	No

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

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

Other hypernyms of human elbow include ginglymoid joint, hinge joint.

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