reunification
noun /ˌriːˌjuːnɪfɪˈkeɪʃn/
  /ˌriːˌjuːnɪfɪˈkeɪʃn/
[uncountable]- the act of joining together two or more regions or parts of a country so that they form a single political unit again重新统一 - the reunification of Germany德国的重新统一 
 
- the reunification of Germany