Cultural diversity has two main roots in contemporary societies. When the plurality of cultures is linked with migration trends, we are facing multicultural societies or, to use Will Kymlicka’s words, polyethnic societies. National diversity is something else: “it arises from the incorporation of previously self-governing, territorially concentrated cultures into a single state”. However, contrary to Kymlicka, I do not think we should call all countries which contain “incorporated national cultures” “multinational states”. It overstretches the concept of “multinational state” while emptying the concept of nation-state: according to that definition, almost all countries in the world would be defined as “multinational states”, the exceptions being Iceland and the Koreas commonly cited as two countries which are made up of a homogeneous ethnonational group. The concept of “multinational state” should be used in a more restrictive way, not only in order to save it as an analytical tool, but because there are two distinct features of national plurality. The first is one where a generally unitary state contains “national minorities” i.e. groups of people which are a minority in that state but whose kin-group is a majority in a neighboring state. A typical case in Eastern Europe is the case of Romania and Slovakia which have important Magyar national minorities (linked, in various ways, with the neighboring Republic of Hungary): those states should be defined as nation-states with national minorities. The other feature of national plurality is the one where a state contains two or more nations (understood as historic/cultural communities). Only when states contain such internal nations should they be called multinational states. Examples of such internal nations are the Basque country, Catalonia and Galicia in Spain, Scotland in the UK, Flanders in Belgium, Quebec in Canada… and in the non Western World, Tatarstan, Chechnya in Russia, Tibet and the Uyghur region in China, “Kurdistan” in Iraq and many others.