Volksdeutsche(r) — "German in terms of people/folk" —, defined ethnically, is a historical term from the 20th century. The words volk and volkische conveyed in Nazi thinking the meanings of "folk" and "race" while adding the sense of superior civilization and blood. These terms were used by Nazis to define people in terms of their ethnicity rather than citizenship and thus included Germans living beyond the borders of the Reich. This is in contrast to Imperial Germans (Reichsdeutsche), German citizens living within Germany. The term also contrasts with the usage of the term Auslandsdeutsche (Germans abroad) since 1936, which generally denotes German citizens residing in other countries.
Volksdeutsche were further divided into Volksgruppen — a minority within a minority in a state — with a special cultural, social and historic development as described by Nazis.
Read more about Volksdeutsche: Origin of The Term, The Nazi Era Before World War II, Expulsion and Exodus From Central and Eastern Europe At The End of The War, Legacy