musculoskeletal system vs skeleton

musculoskeletal system and skeleton both are nouns.

Word	Noun	Adjective	Verb	Adverb
musculoskeletal system	Yes	No	No	No
skeleton	Yes	No	No	No

musculoskeletal system (noun)	skeleton (noun)
the system of muscles and tendons and ligaments and bones and joints and associated tissues that move the body and maintain its form	the internal supporting structure that gives an artifact its shape
	the hard structure (bones and cartilages) that provides a frame for the body of an animal
	a scandal that is kept secret
	something reduced to its minimal form