Dude, its Wikipedia.
Norway, Sweden and Denmark are the three Scandinavian countries. Finland and Iceland are sometimes included in a broader definition by some, but the correct term for all is the Nordic countries.
Finland and Iceland are not considered part of Scandinavia geographically.
If you’re speaking of a specific current geographic or political context, “Scandinavia” means the region that includes Denmark, Sweden, Norway, and the Faroe Islands. If you’d like to include Finland and Iceland in that same context, use the word “Nordic.”
I think thats enough about that topic.