skeleton vs skeletal system

skeleton and skeletal system both are nouns.

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

As nouns, skeleton and skeletal system are synonyms defined as:

skeleton and skeletal system: the hard structure (bones and cartilages) that provides a frame for the body of an animal

Other synonyms of skeleton include frame, systema skeletale.

skeleton (noun)	skeletal system (noun)
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
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