It could also be: cultural, religious, 'anthropologous', geological.

Or a group of people united by a shared currency.

That's not even the entire EU :-)

Everyone knows where and what America is.

Really? Is it everything from Tierra del Fuego to the Barents Sea? Or is it the area of NAFTA? Or all areas controlled by the USA? (Is Puerto Rico America?) Or only the areas of the USA where people can vote for President and senators? Or as often in people's minds, only the contiguous 49 states?

Which brings me back to comment that:

It's all so frustrating to me.

Here is something Emmanuel Todt (the French sociologist/demographer who correctly predicted the collapse of the Soviet Union, and who recently predicted the same for the USA) called my attention to: that in the 'Anglo-Saxon culture' (itself a very vague term, but useful for the moment), the opposed allowance of variation and need for categorisation leads to the maxim, "you have to draw a line somewhere".

Only, I think reality is more complex. One has to accept multiple concepts of 'Europe'. It refers to the tectonical unit delimited by the once collision with the Siberian craton (the Urals), the island chains and mini-continents in the long gone Thethis Ocean (Caucasus Mountains etc.). It refers to the mapping convention roughly delimited by the same borders plus the sea breakthrough between the Mediterranean and the Black Sea. It refers to the traditional areas of Christianity. It refers to the areas affected by the Enlightement in the 18th and early 19th century minus (former) colonies. It refers to the traditional dwelling area of 'white people', alternatively: speakers of Indo-German and Finno-Ugric (and Basque) languages. It refers to all the member states of UEFA or Eurovision (an area from Vladivostok to Ankara, Jerusalem and Lisbon). It refers to the current and future EU (which currently heavily debates the joining of Turkey, but not everyone is against Russia joining in a further future, and let's not forget Morocco wants to join too). It refers to the EU countries and their non-member neighbours that run a welfare state. It refers to the Eurozone (which contains only 12 EU members of 25, but also contains 3 mini-states which aren't EU members). It refers to the  Schengen zone within which there are no border controls (again not all EU members, but Norway is in it).

Europe is an amorphous hodge-podge term, its meaning and geographical reach depends on context.

_{*Lunatic*, n.
One whose delusions are out of fashion.}