'Eastern Europe' has been an accepted term for as long as I can remember for Poland, Romania, Hungary, East Germany (or if you want to be politically correct 'The German Democratic (!!) Republic'), what used to be Czechoslovakia, Bulgaria, Yugoslavia, Lithuania, Latvia and Estonia. Other countries, like Ukraine, might be eastern European but were lumped under the USSR.
'Western Europe' is everywhere else in Europe, including countries like Finland, which of course is much further east than Poland! But everyone knew what was being talked about. The terms still sticks though the politics (and the names of countries like Yugoslavia) might have changed.
