unification vs merger

unification and merger both are nouns.

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

As nouns, unification and merger are synonyms defined as:

unification and merger: an occurrence that involves the production of a union

Other synonyms of unification include fusion.

unification (noun)	merger (noun)
the act of making or becoming a single unit	the combination of two or more commercial companies
an occurrence that involves the production of a union	an occurrence that involves the production of a union
the state of being joined or united or linked