accede vs accession

accede is not a noun while accession is a noun.

Word	Noun	Adjective	Verb	Adverb
accede	No	No	Yes	No
accession	Yes	No	Yes	No

accede (noun)	accession (noun)
	the act of attaining or gaining access to a new office or right or position (especially the throne)
	the right to enter
	agreeing with or consenting to (often unwillingly)
	something added to what you already have
	(civil law) the right to all of that which your property produces whether by growth or improvement
	a process of increasing by addition (as to a collection or group)

accede (verb)	accession (verb)
yield to another's wish or opinion	make a record of additions to a collection, such as a library
to agree or express agreement
take on duties or office