German

German can mean different things.

Anything related to Germany
German language
Germans, people from Germany or one of the earlier countries in the same area
Germanic peoples, people who speak Germanic languages, including German and some other languages
the early people known as Franks
Holy Roman Empire (843-1806)
German Confederation (1815-1866)
German Empire (1871-1918)
Weimar Republic (1919-1933)
German Democratic Republic or East Germany (1949-1990)

When talking about a person, it can mean someone who lives in Germany, or someone who thinks of himself or herself as 'German'.