Where I'm from, when you say "biggest" country, it's by default population unless specified otherwise. Area really isn't an important metric here (unless your country is tiny), because the ability of economic and industrial output scales with population more than with area. The most logical comparison would be by GDP here, because we're comparing economy.
But for population, which is what I think about when specifying country size without any explanation:
Germany is #3 here. You'll see that Russia and Turkey are partly in Europe and bigger than Germany, but since they're mostly in Asia I think most people wouldn't consider them mainly European but rather mainly Asian. There's bound to be some discussion here since it really isn't very clear cut. I'll rephrase to "Germany is at least the third-biggest country in Europe".
Most of the population of Russia is in Europe and it was always considered European country, just like Britain, France, Spain or Portugal of the colonial period.
That's definitely fair. I just blurped it out that way because, at least in my experience, Russia isn't really considered a European country "colloquially". At least where I'm from, people would usually say it's Asian when asked what continent Russia belongs to (if they had to pick one).
But I agree it doesn't really hold up to more detailed scrutiny.
Chill... It's not like they're saying it publicly within earshot. Only the Finns, Latvians, Estonians, Lithuanians, Polish, Ukrainians and Moldovans do that.
It may be unintuitive to you, but "the biggest" in many cases means "most populous" and Germany is that - we don't count Russia (because it is not entirely in Europe) or Turkey (for a similar reason) really.
Err, what? #6 https://en.wikipedia.org/wiki/List_of_European_countries_by_...