The countries of eastern and central Europe which were under Soviet domination from the end of the Second World War until the collapse of the Soviet communist system in 1989–91.
Definition of Eastern bloc in US English:
Eastern bloc
proper nounˈēstərn ˌbläk
The countries of eastern and central Europe that were under Soviet domination from the end of World War II until the collapse of the Soviet communist system in 1989–91, usually considered to include Poland, East Germany, Czechoslovakia, Hungary, Romania, Bulgaria, and Yugoslavia.