marriage vs unification

marriage and unification both are nouns.

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

As nouns, unification is a hypernym of marriage; that is, unification is a word with a broader meaning than marriage:

Other hypernyms of marriage include union.

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