unification

(noun) an occurrence that involves the production of a union. Synonyms: fusion, merger.

(noun) the state of being joined or united or linked. Synonyms: union. Example: "There is strength in union."

(noun) the act of making or becoming a single unit. Synonyms: union, uniting, conjugation, jointure. Examples: "The union of opposing factions." "He looked forward to the unification of his family for the holidays."