subside vs subsidence

subside is not a noun while subsidence is a noun.

Word	Noun	Adjective	Verb	Adverb
subside	No	No	Yes	No
subsidence	Yes	No	No	No

subside (noun)	subsidence (noun)
	a gradual sinking to a lower level
	the sudden collapse of something into a hollow beneath it
	an abatement in intensity or degree (as in the manifestations of a disease)

subside (verb)	subsidence (verb)
wear off or die down
sink down or precipitate
sink to a lower level or form a depression
descend into or as if into some soft substance or place