cubitus vs elbow joint

cubitus and elbow joint both are nouns.

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

As nouns, cubitus and elbow joint are synonyms defined as:

cubitus and elbow joint: hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped

Other synonyms of cubitus include articulatio cubiti, cubital joint, elbow, human elbow.

cubitus (noun)	elbow joint (noun)
hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped	hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped
the arm from the elbow to the fingertips