underframe vs skeleton

underframe and skeleton both are nouns.

Word	Noun	Adjective	Verb	Adverb
underframe	Yes	No	No	No
skeleton	Yes	No	No	No

As nouns, underframe and skeleton are synonyms defined as:

underframe and skeleton: the internal supporting structure that gives an artifact its shape

Other synonyms of underframe include frame, skeletal frame.

underframe (noun)	skeleton (noun)
the internal supporting structure that gives an artifact its shape	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