Nationalism is an idea and movement that promotes the interests of a particular nation (as in a group of people), especially with the aim of gaining and maintaining the nation's sovereignty (self-governance) over its homeland.
The term “nationalism” is generally used to describe two phenomena:
1) the attitude that the members of a nation have when they care about their national identity, and
2) the actions that the members of a nation take when seeking to achieve (or sustain) self-determination.