Can European countries join the European Union?

All the members of the European Union are European countries. Not all European countries are members. There are no countries in it that are not from Europe. However, Turkey, which is mainly in Asia, having just a very small part of it in Europe is currently a candidate for admission.

For a country to even be considered for admission, they must be seen as a European or Europeanized country. Europeanized meaning having heavy European influence, relatable culture and views, and a majority or large European population.