An ethnic group is a group of human beings whose members identify with each other, usually on the basis of preferential endogamy and/or a presumed or real common ancestry.Smith 1987 Ethnic identity is further marked by the recognition from others of a group's distinctiveness"Anthropology. The study of ethnicity, minority groups, and identity," ''Encyclopaedia Britannica, 2007. and the recognition of common cultural, linguistic, religious, behavioral or biological traits,Statistics Canada Definition of Ethnicity real or presumed, as indicators of contrast to other groups.

Ethnicity is an increasingly important means by which states and scientists can identify (and categorise) people,Fact: date=September 2008 and through which people can identify themselves. According to "Challenges of Measuring an Ethnic World: Science, politics, and reality", a conference organized by Statistics Canada and the United States Census Bureau (April 1-3, 1992), "Ethnicity is a fundamental factor in human life: it is a phenomenon inherent in human experience." However, many social scientists, like anthropologists Fredrik Barth and Eric Wolf, regard ethnicity more as a product of interaction, rather than reflecting essential qualities inherent to human groups. Processes that result in the emergence of such identification are called ethnogenesis. Members of an ethnic group, on the whole, claim cultural continuities over time, although historians and cultural anthropologists have documented that many of the values, practices, and norms that imply continuity with the past are of relatively recent invention.

Definition

The sociologist Max Weber once remarked that "the whole conception of ethnic groups is so complex and so vague that it might be good to abandon it altogether."Max Weber 11978 Economy and Society eds. Guenther Roth and Claus Wittich, trans. Ephraim Fischof, vol. 2 Berkeley: University of California Press, 389

In any case, Weber proposed a definition of ethnic group that became accepted by many sociologistsFact: date=March 2008:

2hose human groups that entertain a subjective belief in their common descent because of similarities of physical type or of customs or both, or because of memories of colonization and migration; this belief must be important for group formation; furthermore it does not matter whether an objective blood relationship exists.

Anthropologist Ronald Cohen, in a review of anthropological and sociological studies of ethnic groups since Weber, claimed that the identification of "ethnic groups" by social scientists often reflected inaccurate labels more than indigenous realities:

... the named ethnic identities we accept, often unthinkingly, as basic givens in the literature are often arbitrarily, or even worse inaccurately, imposed.Ronald Cohen 1978 "Ethnicity: Problem and Focus in Anthropology" in Annual Review of Anthropology 7: 383 Palo Alto: Stanford University Press