supplementation vs expansion

supplementation and expansion both are nouns.

Word	Noun	Adjective	Verb	Adverb
supplementation	Yes	No	No	No
expansion	Yes	No	No	No

As nouns, expansion is a hypernym of supplementation; that is, expansion is a word with a broader meaning than supplementation:

Other hypernyms of supplementation include expanding upon.

supplementation (noun)	expansion (noun)
the act of supplementing	the act of increasing (something) in size or volume or quantity or scope
a quantity added (e.g. to make up for a deficiency)	adding information or detail
	a discussion that provides additional information
	a function expressed as a sum or product of terms