Plurinationalism, or plurinationality is the coexistence of two or more preserved national groups within a single polity, usually a nation state.
In circumstances where the Leninist conception of national self-determination is not necessary (i.e. the minority nation does not wish to secede into a new nation-state) nations can be adequately protected and represented by a plurinational state.
One example of this is the socialist state of Bolivia, which maintains the line of plurinationality in order to preserve the national character of indigenous groups while also dealing with the historical facts of colonization; particularly the large Mestizo population.