Eastern Europe is a region lying in the Eastern part of Europe. The term is highly context-dependent and there are "almost as many definitions of Eastern Europe as there are scholars of the region". A related UN paper adds that "every assessment of spatial identities is essentially a social and cultural construct".

One prevailing definition describes Eastern Europe as a cultural entity: the region lying between Central Europe and Western Asia, with main characteristics consisting in Byzantine, Orthodox and limited Ottoman influences. Another definition, considered outdated by some authors, was created during the Cold War and used more or less synonymously with the term Eastern Bloc, including the countries that historically and geographically belong to Central Europe. A third definition names the formerly Communist European states outside the Soviet Union as Eastern Europe, though these countries are more commonly known as the constituents of Central and Eastern Europe.