An ethnicity or ethnic group is a group of people who identify with each other on the basis of perceived shared attributes that distinguish them from other groups. Those attributes can include a common nation of origin, or common sets of ancestry, traditions, language, history, society, religion, or social treatment. The term ethnicity is often used interchangeably with the term nation, particularly in cases of ethnic nationalism.

The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. Its definition is contested, in part due to conflicting theoretical understandings of social and kinship structures, and also reflecting the problematic application of this concept to extremely diverse human societies. The concept is often contrasted by anthropologists with other social and kinship groups, being hierarchically larger than a lineage or clan, but smaller than a chiefdom, ethnicity, nation or state. These terms are similarly disputed. In some cases tribes have legal recognition and some degree of political autonomy from national or federal government, but this legalistic usage of the term may conflict with anthropological definitions.