expand vs expansion

expand is not a noun while expansion is a noun.

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

expand (noun)	expansion (noun)
	the act of increasing (something) in size or volume or quantity or scope
	adding information or detail
	a discussion that provides additional information
	a function expressed as a sum or product of terms

expand (verb)	expansion (verb)
grow vigorously
exaggerate or make bigger
become larger in size or volume or quantity
expand the influence of
make bigger or wider in size, volume, or quantity
add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing
extend in one or more directions