human elbow vs arm

human elbow and arm both are nouns.

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

human elbow (noun)	arm (noun)
hinge joint between the forearm and upper arm and the corresponding joint in the forelimb of a quadruped	the part of a garment that is attached at the armhole and that provides a cloth covering for the arm
	any instrument or instrumentality used in fighting or hunting
	the part of an armchair or sofa that supports the elbow and forearm of a seated person
	any projection that is thought to resemble a human arm
	a human limb; technically the part of the superior limb between the shoulder and the elbow but commonly used to refer to the whole superior limb
	a division of some larger or more complex organization

human elbow (verb)	arm (verb)
	prepare oneself for a military confrontation
	supply with arms