but it depends on time
in 50's could be iron curtain
in another time like the schisma of the church could be the areas that exist Orthodox Churces, and west could be the area of the Catholic churches,
in linguistic means mainly the Slavic and Baltic languages including Albania, (greece hungary are not not)
you can also compare to karlomagnus as west Europe,
it depends the criteria you put,
but mainly the terminology is not according map, but according the discussion,
for example Slovenia could be East Europe to Cold war times, East Europe due to Satem language and Slavic connection, West Europe due to Catholic church etc. but it is in the middle of Europe.