Europe refers to a geographical area and a civilization. In the former sense it stretches in the West from Gibraltar to the British Isles, in the East to the Urals, and on the South to the Mediterranean, Black Sea, Caucasus and Caspian Sea. In the latter sense it has usually been more restricted. Napoleon said that Europe ends at the Pyrenees, and Goethe said somewhere (I believe) that he left Europe when he stepped into a peasant’s cottage. There has always been a question whether Russia or the Balkans are truly European.
The relation between Europe and its offspring has further complicated the question. Is America European?
The extent of European civilization in time is also debatable. Was its true founder the Greeks? Pope Gregory the Great? Charlemagne?