Ethnic nationalism
Ethnic nationalism is a form of nationalism
Nationalism is a political ideology that involves a strong identification of a group of individuals with a political entity defined in national terms, i.e. a nation. In the 'modernist' image of the nation, it is nationalism that creates national identity. There are various definitions for what...

 wherein the "nation
A nation may refer to a community of people who share a common language, culture, ethnicity, descent, and/or history. In this definition, a nation has no physical borders. However, it can also refer to people who share a common territory and government irrespective of their ethnic make-up...

" is defined in terms of ethnicity. Whatever specific ethnicity is involved, ethnic nationalism always includes some element of descent
Kinship is a relationship between any entities that share a genealogical origin, through either biological, cultural, or historical descent. And descent groups, lineages, etc. are treated in their own subsections....

 from previous generations and the implied claim of ethnic essentialism, i.e. the understanding of ethnicity as an essence that remains unchanged over time.

The central theme of ethnic nationalists is that "..nations are defined by a shared heritage, which usually includes a common language, a common faith, and a common ethnic ancestry." It also includes ideas of a culture
Culture is a term that has many different inter-related meanings. For example, in 1952, Alfred Kroeber and Clyde Kluckhohn compiled a list of 164 definitions of "culture" in Culture: A Critical Review of Concepts and Definitions...

 shared between members of the group, and with their ancestors, and usually a shared language; however it is different from purely cultural definitions of "the nation" (which allow people to become members of a nation by cultural assimilation
Cultural assimilation
Cultural assimilation is a socio-political response to demographic multi-ethnicity that supports or promotes the assimilation of ethnic minorities into the dominant culture. The term assimilation is often used with regard to immigrants and various ethnic groups who have settled in a new land. New...

) and a purely linguistic definitions (which see "the nation" as all speakers of a specific language).