addendum vs matter

addendum and matter both are nouns.

Word	Noun	Adjective	Verb	Adverb
addendum	Yes	No	No	No
matter	Yes	No	Yes	No

As nouns, matter is a hypernym of addendum; that is, matter is a word with a broader meaning than addendum:

addendum: textual matter that is added onto a publication; usually at the end
matter: written works (especially in books or magazines)

addendum (noun)	matter (noun)
textual matter that is added onto a publication; usually at the end	that which has mass and occupies space
	(used with negation) having consequence
	some situation or event that is thought about
	a vaguely specified concern
	a problem
	written works (especially in books or magazines)

addendum (verb)	matter (verb)
	have weight; have import, carry weight