A clan is a group of people united by actual or perceived kinship and descent. Even if lineage details are unknown, clan members may be organized around a founding member or apical ancestor. The kinship-based bonds may be symbolical, whereby the clan shares a "stipulated" common ancestor that is a symbol of the clan's unity. When this "ancestor" is non-human, it is referred to as a totem, which is frequently an animal. Clans can be most easily described as tribes or sub-groups of tribes. The word clan is derived from 'clann' meaning 'family' in the Irish and Scottish Gaelic languages. The word was taken into English about 1425 as a label for the tribal nature of Irish and Scottish Gaelic society. Clans in indigenous societies are likely to be exogamous, meaning that their members cannot marry one another. Clans preceded more centralized forms of community organization and government; they are located in every country. Members may identify with a coat of arms or other symbol to show they are an independent clan.
In different cultures and situations, a clan may mean the same thing as other kin-based groups, such as tribes, castes, and bands. Often, the distinguishing factor is that a clan is a smaller part of a larger society such as a tribe, a chiefdom, or a state. In some societies, clans may have an official leader such as a chieftain or patriarch; in others, leadership positions may have to be achieved, or people may say that 'elders' make decisions.
Examples include Irish, Scottish, Chinese, Japanese clans, Rajput clans, Nair Clan or Malayala Kshatriya Clan in India and Pakistan, which exist as kin groups within their respective nations. Note, however, that tribes and bands can also be components of larger societies. However, the early Norse clans, the ætter, cannot be translated with tribe or band, and consequently they are often translated as house or line. The Biblical tribes of Israel were composed of many clans, Arab clans are sub-tribal groups within Arab society. Ojibwa bands are smaller parts of the Ojibwa tribe or people in North America, as one example of the many Native American peoples distinguished by language and culture, most having clans and bands as the basic kinship organizations. In some cases more than one tribe recognized each other's clans; for instance, both the Chickasaw and Choctaw tribes had fox and bear clans whose membership could supersede the tribe.