Ostgebiete

Etymology 1
From. Short for.

Noun

 * 1)  the pre-1938 territories of the German Reich east of the Oder-Neisse line, from where the German population was expelled after World War II, and which are now parts of Poland and Russia
 * 2)  the even vaster pre-1918 territories of the Reich as well as, possibly, the Sudetenland, which was German between 1938 and 1945 (areas conquered during WWII are never included)

Usage notes

 * In 1990, the Federal Republic of Germany officially dropped its claim to the territories (having generally not referred to the claims since the normalization of relations in 1970). Since then, and even sometimes before, they have often been referred to as.

Etymology 2
Inflected forms.