- a former province in NE Germany: an enclave separated from Germany by the Polish Corridor; now divided between Poland and the Russian Federation. 14,283 sq. mi. (36,993 sq. km). Capital: Königsberg.
- a former province of NE Germany on the Baltic Sea: separated in 1919 from the rest of Germany by the Polish Corridor and Danzig: in 1945 Poland received the south part, the Soviet Union the northGerman name: Ostpreussen (ostˈprɔysən)