Answer:
Nationalism is a very tricky thing to describe. It is a sense of unifying loyalty/love for one's country.
Cultural Nationalism is one based on a cultural identity, this can have religious and ethnic connotations as well.
Lets examine the Hapsburg (Austrian-Hungarian) Empire. It was a nation dominated by a German (Austrian) elite minority, and its subjects included many Slavs (Czechs, Slovaks, Slovens, Croats, some Serbs, Bosniaks, etc). These slavic subject people were united by a strong yearning for a free nation in which their culture (which was quite different from Austrian-German) could flourish within its own boarders.
Political nationalism is also tricky, but it seems it would be based upon political identities, such a Communism or Democracy in the Cold War.