An ethnic group or an ethnicity is a category of people who identify with each other based on similarities such as common ancestry, language, history, society, culture or nation. Ethnicity is usually an inherited status based on the society in 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.
Ethnic groups, derived from the same historical founder population, often continue to speak related languages and share a similar gene pool. By way of language shift, acculturation, adoption and religious conversion, it is sometimes possible for individuals or groups to leave one ethnic group and become part of another (except for ethnic groups emphasizing homogeneity or racial purity as a key membership criterion).
Ethnicity is often used synonymously with terms such as nation or people. In English, it can also have the connotation of something exotic (cf. “ethnic restaurant”, etc.), generally related to cultures of more recent immigrants, who arrived after the dominant population of an area was established.
The largest ethnic groups in modern times comprise hundreds of millions of individuals (Han Chinese being the largest), while the smallest are limited to a few dozen individuals (numerous indigenous peoples worldwide). Larger ethnic groups may be subdivided into smaller sub-groups known variously as tribes or clans, 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.