Two terms can describe different aspects of the same process.
An explanation of the legal process uses terms such as accession and Unification Treaty. A general account often calls the event “German reunification” or “German unity”. These terms do not contradict one another here; they emphasise different aspects.
The question expressly asks for the common name. “German reunification” therefore fits. The name of a European organisation or an international military alliance answers a different question.
The other three answers
The other answers confuse national unity with an alliance or a European organisation.
NATO Eastern Enlargement
NATO eastern enlargement describes the expansion of a military alliance. It is not the common name for the GDR’s accession to the Federal Republic.
EU Eastern Enlargement
EU eastern enlargement concerns additional countries joining the European Union. This question instead asks about achieving German national unity in 1990.
European Community
“European Community” names a European grouping. It is not the name for the unification of the two German states.
The fall of the Wall and reunification have different dates.
The fall of the Berlin Wall on 9 November 1989 was a decisive step towards unity. It was not already the legal completion of national unification. That is marked by 3 October 1990.
“Reunification” also does not promise that every economic, social or personal difference disappeared immediately. Here, the word identifies national unity. People’s life histories and subsequent developments are broader subjects.
Unity on 3 October 1990 · German Bundestag ↗Accession is the route, reunification the common name, 3 October 1990 the date.
Separate name, process and date. This helps with related questions without treating the fall of the Wall and unity as identical.
Three words for this question
- der Beitrittaccession
- Joining an existing state or grouping through a legal process.
- die Wiedervereinigungreunification
- Previously separated parts coming together again; here, German national unity.
- die Bezeichnungterm or name
- The word used to name an object or process.