unification vs marriage

unification and marriage both are nouns.

Word	Noun	Adjective	Verb	Adverb
unification	Yes	No	No	No
marriage	Yes	No	No	No

As nouns, marriage is a hyponym of unification; that is, marriage is a word with a more specific, narrower meaning than unification:

unification (noun)	marriage (noun)
the act of making or becoming a single unit	the act of marrying; the nuptial ceremony
an occurrence that involves the production of a union	two people who are married to each other
the state of being joined or united or linked	the state of being a married couple voluntarily joined for life (or until divorce)
	a close and intimate union