An ethnic group or ethnicity is a category of people who identify with each other, usually on the basis of a presumed common genealogy or ancestry or on similarities such as common language or dialect, history, society, culture or nation.^[1][2] Ethnicity is often used synonymously with the term nation, particularly in cases of ethnic nationalism, and is separate from but related to the concept of races.

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 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).

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). 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 (such as Han Chinese) 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 term ethnic is derived from the Greek word ἔθνος ethnos (more precisely, from the adjective ἐθνικός ethnikos,^[3] which was loaned into Latin as ethnicus). The inherited English language term for this concept is folk, used alongside the latinate people since the late Middle English period.

In Early Modern English and until the mid-19th century, ethnic was used to mean heathen or pagan (in the sense of disparate "nations" which did not yet participate in the Christian oikumene), as the Septuagint used ta ethne ("the nations") to translate the Hebrew goyim "the nations, non-Hebrews, non-Jews".^[4] The Greek term in early antiquity (Homeric Greek) could refer to any large group, a host of men, a band of comrades as well as a swarm or flock of animals. In Classical Greek, the term took on a meaning comparable to the concept now expressed by "ethnic group", mostly translated as "nation, people"; only in Hellenistic Greek did the term tend to become further narrowed to refer to "foreign" or "barbarous" nations in particular (whence the later meaning "heathen, pagan").^[5]

In the 19th century, the term came to be used in the sense of "peculiar to a race, people or nation", in a return to the original Greek meaning. The sense of "different cultural groups", and in American English "racial, cultural or national minority group" arises in the 1930s to 1940s,^[6] serving as a replacement of the term race which had earlier taken this sense but was now becoming deprecated due to its association with ideological racism. The abstract ethnicity had been used for "paganism" in the 18th century, but now came to express the meaning of an "ethnic character" (first recorded 1953). The term ethnic group was first recorded in 1935 and entered the Oxford English Dictionary in 1972.^[7] Depending on the context that is used, the term nationality may either be used synonymously with ethnicity, or synonymously with citizenship (in a sovereign state). The process that results in the emergence of an ethnicity is called ethnogenesis, a term in use in ethnological literature since about 1950. The term may also be used with 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.

Depending on which source of group identity is emphasized to define membership, the following types of (often mutually overlapping) groups can be identified:

In many cases more than one aspect determines membership: for instance, Armenian ethnicity can be defined by citizenship of Armenia, native use of the Armenian language, or membership of the Armenian Apostolic Church.

Ethnography begins in classical antiquity; after early authors like Anaximander and Hecataeus of Miletus, Herodotus in c. 480 BC laid the foundation of both historiography and ethnography of the ancient world. The Greeks at this time did not describe foreign nations but had also developed a concept of their own "ethnicity", which they grouped under the name of Hellenes. Herodotus (8.144.2) gave a famous account of what defined Greek (Hellenic) ethnic identity in his day, enumerating

Whether ethnicity qualifies as a cultural universal is to some extent dependent on the exact definition used. According to "Challenges of Measuring an Ethnic World: Science, politics, and reality", in Challenges of Measuring an Ethnic World: Science, Politics and Reality : Proceedings of the Joint Canada-United States Conference on the Measurement of Ethnicity, April 1–3, 1992, Joint Canada-United States Conference on the Measurement of Ethnicity, Department of Commerce, Statistics Canada, 1993,^[14] a conference organised by Statistics Canada and the United States Census Bureau (April 1–3, 1992).^[15] Many social scientists, such as anthropologists Fredrik Barth and Eric Wolf, do not consider ethnic identity to be universal. They regard ethnicity as a product of specific kinds of inter-group interactions, rather than an essential quality inherent to human groups.^[16]

According to Thomas Hylland Eriksen, the study of ethnicity was dominated by two distinct debates until recently.

According to Eriksen, these debates have been superseded, especially in anthropology, by scholars' attempts to respond to increasingly politicised forms of self-representation by members of different ethnic groups and nations. This is in the context of debates over multiculturalism in countries, such as the United States and Canada, which have large immigrant populations from many different cultures, and post-colonialism in the Caribbean and South Asia.^[25]

Max Weber maintained that ethnic groups were künstlich (artificial, i.e. a social construct) because they were based on a subjective belief in shared Gemeinschaft (community). Secondly, this belief in shared Gemeinschaft did not create the group; the group created the belief. Third, group formation resulted from the drive to monopolise power and status. This was contrary to the prevailing naturalist belief of the time, which held that socio-cultural and behavioral differences between peoples stemmed from inherited traits and tendencies derived from common descent, then called "race".^[26]

Another influential theoretician of ethnicity was Fredrik Barth, whose "Ethnic Groups and Boundaries" from 1969 has been described as instrumental in spreading the usage of the term in social studies in the 1980s and 1990s.^[27] Barth went further than Weber in stressing the constructed nature of ethnicity. To Barth, ethnicity was perpetually negotiated and renegotiated by both external ascription and internal self-identification. Barth's view is that ethnic groups are not discontinuous cultural isolates, or logical a prioris to which people naturally belong. He wanted to part with anthropological notions of cultures as bounded entities, and ethnicity as primordialist bonds, replacing it with a focus on the interface between groups. "Ethnic Groups and Boundaries", therefore, is a focus on the interconnectedness of ethnic identities. Barth writes: "... categorical ethnic distinctions do not depend on an absence of mobility, contact and information, but do entail social processes of exclusion and incorporation whereby discrete categories are maintained despite changing participation and membership in the course of individual life histories."

In 1978, anthropologist Ronald Cohen claimed that the identification of "ethnic groups" in the usage of social scientists often reflected inaccurate labels more than indigenous realities:

In this way, he pointed to the fact that identification of an ethnic group by outsiders, e.g. anthropologists, may not coincide with the self-identification of the members of that group. He also described that in the first decades of usage, the term ethnicity had often been used in lieu of older terms such as "cultural" or "tribal" when referring to smaller groups with shared cultural systems and shared heritage, but that "ethnicity" had the added value of being able to describe the commonalities between systems of group identity in both tribal and modern societies. Cohen also suggested that claims concerning "ethnic" identity (like earlier claims concerning "tribal" identity) are often colonialist practices and effects of the relations between colonized peoples and nation-states.^[27]

According to Paul James, formations of identity were often changed and distorted by colonization, but identities are not made out of nothing:

Social scientists have thus focused on how, when, and why different markers of ethnic identity become salient. Thus, anthropologist Joan Vincent observed that ethnic boundaries often have a mercurial character.^[29] Ronald Cohen concluded that ethnicity is "a series of nesting dichotomizations of inclusiveness and exclusiveness".^[27] He agrees with Joan Vincent's observation that (in Cohen's paraphrase) "Ethnicity ... can be narrowed or broadened in boundary terms in relation to the specific needs of political mobilization.^[27] This may be why descent is sometimes a marker of ethnicity, and sometimes not: which diacritic of ethnicity is salient depends on whether people are scaling ethnic boundaries up or down, and whether they are scaling them up or down depends generally on the political situation.

Different approaches to understanding ethnicity have been used by different social scientists when trying to understand the nature of ethnicity as a factor in human life and society. As Jonathan M. Hall observes, World War II was a turning point in the ethnic studies. The consequences of Nazi racism discouraged essentialist interpretations of ethnic groups and race. Ethnic groups came to be defined as social rather than as biological entities. Their coherence was attributed to shared myths, descent, kinship, a common place of origin, language, religion, customs and national character. So, ethnic groups are conceived as mutable rather than stable, constructed in discursive practices rather than written in the genes.^[30]

Examples of various approaches are: primordialism, essentialism, perennialism, constructivism, modernism and instrumentalism.

Ethnicity is an important means by which people may identify with a larger group. Many social scientists, such as anthropologists Fredrik Barth and Eric Wolf, do not consider ethnic identity to be universal. They regard ethnicity as a product of specific kinds of inter-group interactions, rather than an essential quality inherent to human groups.^[16] 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.^[37]

Ethnic groups differ from other social groups, such as subcultures, interest groups or social classes, because they emerge and change over historical periods (centuries) in a process known as ethnogenesis, a period of several generations of endogamy resulting in common ancestry (which is then sometimes cast in terms of a mythological narrative of a founding figure); ethnic identity is reinforced by reference to "boundary markers" - characteristics said to be unique to the group which set it apart from other groups.^{[38][39][40][41][42]}

Ethnicity theory says that race is a social category and is but one of several factors in determining ethnicity. Some other criteria include: "religion, language, 'customs,' nationality, and political identification".^[43] This theory was put forth by sociologist Robert E. Park in the 1920s. It is based on the notion of “culture”.

This theory was preceded by over a century where biological essentialism was the dominant paradigm on race. Biological essentialism is the belief that white European races are biologically superior and other non-white races are inherently inferior. This view arose as a way to justify slavery of Africans and genocide of the Native Americans in a society which was supposedly founded on freedom for all. This was a notion that developed slowly and came to be a preoccupation of scientists, theologians, and the public. Religious institutions asked questions about whether there had been multiple genesis's (polygenesis) and whether God had created lesser races of men. Many of the foremost scientists of the time took up idea of racial difference. They would inadvertently find that white Europeans were superior. One method that was used was the measurement of cranial capacity.^[44]

Ethnicity theory was based on the assimilation model. Park outlined his four steps to assimilation: contact, conflict, accommodation, and assimilation. Instead of explaining the marginalized status of people of color in the United States with an inherent biological inferiority, he instead said that it was a failure to assimilate into American culture that held people back. They could be equal as long as they dropped their culture which was deficient compared to white culture.

Michael Omi and Howard Winant's theory of racial formation directly confronts both ethnicity theory's premises and practices. They argue in Racial Formation in the United States that ethnicity theory was exclusively based on the immigration patterns of a white ethnic population and did not account for the unique experiences of non-whites in this country.^[45] While this theory identities different stages in an immigration process – contact, conflict, struggle, and as the last and best response, assimilation – it did so only for white ethnic communities.^[45] The ethnicity paradigm neglects the ways that race can complicate a community's interactions with basic social and political structures, especially upon contact.

And assimilation – shedding the particular qualities of a native culture for the purpose of blending in with a host culture – did not work for some groups as a response to racism and discrimination as it did for others.^[45] Moreover, once the legal barriers to achieving equality had been dismantled, the problem of racism became the sole responsibility of already disadvantaged communities.^[46] It was assumed that if a Black or Latino community was not 'making it' by the standards that had been set by white ethnics, it was because that community did not hold the right values or beliefs. Or they must be stubbornly resisting dominant norms because they did not want to fit in. Omi and Winant's critique of ethnicity theory explains how looking towards a cultural defect for the source of inequality ignores the "concrete sociopolitical dynamics within which racial phenomena operate in the U.S."^[47] In other words, buying into this approach effectively strips us of our ability to critically examine the more structural components of racism and encourages, instead, a “benign neglect” of social inequality.^[47]

In some cases, especially involving transnational migration, or colonial expansion, ethnicity is linked to nationality. Anthropologists and historians, following the modernist understanding of ethnicity as proposed by Ernest Gellner^[48] and Benedict Anderson^[49] see nations and nationalism as developing with the rise of the modern state system in the 17th century. They culminated in the rise of "nation-states" in which the presumptive boundaries of the nation coincided (or ideally coincided) with state boundaries. Thus, in the West, the notion of ethnicity, like race and nation, developed in the context of European colonial expansion, when mercantilism and capitalism were promoting global movements of populations at the same time that state boundaries were being more clearly and rigidly defined.

In the 19th century, modern states generally sought legitimacy through their claim to represent "nations." Nation-states, however, invariably include populations that have been excluded from national life for one reason or another. Members of excluded groups, consequently, will either demand inclusion on the basis of equality, or seek autonomy, sometimes even to the extent of complete political separation in their own nation-state.^[50] Under these conditions – when people moved from one state to another,^[51] or one state conquered or colonized peoples beyond its national boundaries – ethnic groups were formed by people who identified with one nation, but lived in another state.

Multi-ethnic states can be the result of two opposite events, either the recent creation of state borders at variance with traditional tribal territories, or the recent immigration of ethnic minorities into a former nation state. Examples for the first case are found throughout Africa, where countries created during decolonisation inherited arbitrary colonial borders, but also in European countries such as Belgium or United Kingdom. Examples for the second case are countries such as Germany or the Netherlands, which were relatively ethnically homogeneous when they attained statehood but have received significant immigration during the second half of the 20th century. States such as the United Kingdom, France and Switzerland comprised distinct ethnic groups from their formation and have likewise experienced substantial immigration, resulting in what has been termed "multicultural" societies especially in large cities.

The states of the New World were multi-ethnic from the onset, as they were formed as colonies imposed on existing indigenous populations.

In recent decades feminist scholars (most notably Nira Yuval-Davis)^[52] have drawn attention to the fundamental ways in which women participate in the creation and reproduction of ethnic and national categories. Though these categories are usually discussed as belonging to the public, political sphere, they are upheld within the private, family sphere to a great extent.^[53] It is here that women act not just as biological reproducers but also as 'cultural carriers', transmitting knowledge and enforcing behaviours that belong to a specific collectivity.^[54] Women also often play a significant symbolic role in conceptions of nation or ethnicity, for example in the notion that 'women and children' constitute the kernel of a nation which must be defended in times of conflict, or in iconic figures such as Britannia or Marianne.

Race and ethnicity are considered as related concepts. Ethnicity is used as a matter of cultural identity of a group, often based on shared ancestry, language and cultural traditions, while race is applied as a pseudoscientific grouping, based on physical similarities within groups. Race is a more controversial subject than ethnicity, due to common political use of the term. It is assumed that, based on power relations, there exist "racialized ethnicities" and "ethnicized races". Ramón Grosfoguel (University of California, Berkeley) argues that 'racial/ethnic identity' is one concept and that concepts of race and ethnicity cannot be used as separate and autonomous categories.^[55]

Before Weber (1864-1920), race and ethnicity were primarily seen as two aspects of the same thing. Around 1900 and before, the essentialist primordialist understanding of ethnicity predominated: cultural differences between peoples were seen as being the result of inherited traits and tendencies.^[56] With Weber's introduction of the idea of ethnicity as a social construct, race and ethnicity became more divided from each other.

In 1950 the UNESCO statement, "The Race Question", signed by some of the internationally renowned scholars of the time (including Ashley Montagu, Claude Lévi-Strauss, Gunnar Myrdal, Julian Huxley, etc.), stated:

In 1982 anthropologist David Craig Griffith summed up forty years of ethnographic research, arguing that racial and ethnic categories are symbolic markers for different ways that people from different parts of the world have been incorporated into a global economy:

According to Wolf, racial categories were constructed and incorporated during the period of European mercantile expansion, and ethnic groupings during the period of capitalist expansion.^[59]

Writing in 1977 about the usage of the term "ethnic" in the ordinary language of Great Britain and the United States, Wallman noted that

In the U.S., the OMB defines the concept of race as outlined for the US Census as not "scientific or anthropological" and takes into account "social and cultural characteristics as well as ancestry", using "appropriate scientific methodologies" that are not "primarily biological or genetic in reference".^[61]

Sometimes ethnic groups are subject to prejudicial attitudes and actions by the state or its constituents. In the 20th century, people began to argue that conflicts among ethnic groups or between members of an ethnic group and the state can and should be resolved in one of two ways. Some, like Jürgen Habermas and Bruce Barry, have argued that the legitimacy of modern states must be based on a notion of political rights of autonomous individual subjects. According to this view, the state should not acknowledge ethnic, national or racial identity but rather instead enforce political and legal equality of all individuals. Others, like Charles Taylor and Will Kymlicka, argue that the notion of the autonomous individual is itself a cultural construct. According to this view, states must recognize ethnic identity and develop processes through which the particular needs of ethnic groups can be accommodated within the boundaries of the nation-state.

The 19th century saw the development of the political ideology of ethnic nationalism, when the concept of race was tied to nationalism, first by German theorists including Johann Gottfried von Herder. Instances of societies focusing on ethnic ties, arguably to the exclusion of history or historical context, have resulted in the justification of nationalist goals. Two periods frequently cited as examples of this are the 19th century consolidation and expansion of the German Empire and the 20th century Nazi Germany. Each promoted the pan-ethnic idea that these governments were only acquiring lands that had always been inhabited by ethnic Germans. The history of late-comers to the nation-state model, such as those arising in the Near East and south-eastern Europe out of the dissolution of the Ottoman and Austro-Hungarian Empires, as well as those arising out of the former USSR, is marked by inter-ethnic conflicts. Such conflicts usually occur within multi-ethnic states, as opposed to between them, as in other regions of the world. Thus, the conflicts are often misleadingly labelled and characterized as civil wars when they are inter-ethnic conflicts in a multi-ethnic state.

Ethnic groups in Africa number in the hundreds, each generally having its own language (or dialect of a language) and culture.

Many ethnic groups and nations of Africa qualify, although some groups are of a size larger than a tribal society. These mostly originate with the Sahelian kingdoms of the medieval period, such as that of the Akan, deriving from Bonoman (11th century) then the Kingdom of Ashanti (17th century).^[62]

There is an abundance of ethnic groups throughout Asia, with adaptations to the climate zones of Asia, which can be Arctic, subarctic, temperate, subtropical or tropical. The ethnic groups have adapted to mountains, deserts, grasslands, and forests.

On the coasts of Asia, the ethnic groups have adopted various methods of harvest and transport. Some groups are primarily hunter-gatherers, some practice transhumance (nomadic lifestyle), others have been agrarian/rural for millennia and others becoming industrial/urban. Some groups/countries of Asia are completely urban, such as those in Hong Kong, Shanghai and Singapore. The colonization of Asia was largely ended in the 20th century, with national drives for independence and self-determination across the continent.

Europe has a large number of ethnic groups; Pan and Pfeil (2004) count 87 distinct "peoples of Europe", of which 33 form the majority population in at least one sovereign state, while the remaining 54 constitute ethnic minorities within every state they inhabit (although they may form local regional majorities within a sub-national entity). The total number of national minority populations in Europe is estimated at 105 million people, or 14% of 770 million Europeans.^[64]

A number of European countries, including France,^[65] and Switzerland do not collect information on the ethnicity of their resident population.

Russia has over 185 recognized ethnic groups besides the 80% ethnic Russian majority. The largest group are the Tatars 3.8%. Many of the smaller groups are found in the Asian part of Russia (see Indigenous peoples of Siberia).

An example of a largely nomadic ethnic group in Europe is the Roma, pejoratively known as Gypsies. They originated from India and speak the Romani language.