An ethnic group or ethnicity is a grouping of people who identify with each other on the basis of shared attributes that distinguish them from other groups such as a common set of traditions, ancestry, language, history, society, culture, nation, religion, or social treatment within their residing area. Ethnicity is sometimes used interchangeably with the term nation, particularly in cases of ethnic nationalism, and is separate from, but related to the concept of races.
Ethnicity can be an inherited status or based on the society within which one lives. Membership of an ethnic group tends to be defined by a shared cultural heritage, ancestry, origin myth, history, homeland, language, or dialect, symbolic systems such as religion, mythology and ritual, cuisine, dressing style, art, or physical appearance. Moreover, ethnic groups are also defined by genetics. Ethnic groups often continue to speak related languages.
By way of language shift, acculturation, adoption and religious conversion, individuals or groups may over time shift from one ethnic group to another. Ethnic groups may be subdivided into subgroups or tribes, which over time may become separate ethnic groups themselves due to endogamy or physical isolation from the parent group. Conversely, formerly separate ethnicities can merge to form a pan-ethnicity and may eventually merge into one single ethnicity. Whether through division or amalgamation, the formation of a separate ethnic identity is referred to as ethnogenesis.
The nature of ethnicity is still debated by scholars. 'Primordialists' view ethnic groups as real phenomena whose distinct characteristics have endured since the distant past. Others view ethnic groups as a social construct, an identity which is assigned based on rules made by society..
Ethnic groups are shown to be different in exposure and sensitivity to adversity. A widely described phenomenon is marginalization-related diminished returns (MDRs) that suggests because of social stratification, ethnic minorities remain at risk of health problems, even when they have upward social mobility. This theory suggests that upward social mobility is more taxing for ethnic minority people, thus middle-class ethnic minority people would still have worse-than-expected health. An example MDR is that highly educated Latino people remain at risk of binge drinking because their education shows weaker protective effects than non-Latino people. This topic is the focus of the marginalization-related diminished returns (MDRs) research center in Los Angeles.