> (also Finland isn't part of Scandinavia)

The Scandinavian countries are easy to recognize based on their flags, as we all share the same pattern on our flags, a cross with the center slightly to the left. https://en.wikipedia.org/wiki/Scandinavia

In English use it is commonly seen as included as part of Scandinavia. Ditto Iceland (even more improbable).

Scandinavia: Denmark, Sweden and Norway.

Nordic countries: Scandinavia, Finland, Iceland (and Faroe)