residuum vs component part

residuum and component part both are nouns.

Word	Noun	Adjective	Verb	Adverb
residuum	Yes	No	No	No
component part	Yes	No	No	No

As nouns, component part is a hypernym of residuum; that is, component part is a word with a broader meaning than residuum:

residuum: something left after other parts have been taken away
component part: something determined in relation to something that includes it

Other hypernyms of residuum include component, constituent, part, portion.

residuum (noun)	component part (noun)
something left after other parts have been taken away	something determined in relation to something that includes it