Sib is a technical term in the discipline of anthropology

Anthropology

Anthropology is the study of humanity. It has origins in the humanities, the natural sciences, and the social sciences. The term "anthropology" is from the Greek anthrōpos , "man", understood to mean mankind or humanity, and -logia , "discourse" or "study", and was first used in 1501 by German...

  which originally denoted a kinship

Kinship

Kinship is a relationship between any entities that share a genealogical origin, through either biological, cultural, or historical descent. And descent groups, lineages, etc. are treated in their own subsections....

 group

Sippe

Sippe is German for "clan, kindred, extended family". It continues a Proto-Germanic term *sibbja, which referred to a band or confederation bound by a treaty or oath, not primarily restricted to blood relations. The original character of sibb as a peace treaty is visible in Old English, e.g. in...

 among Anglo-Saxon

Anglo-Saxons

Anglo-Saxon is a term used by historians to designate the Germanic tribes who invaded and settled the south and east of Great Britain beginning in the early 5th century AD, and the period from their creation of the English nation to the Norman conquest. The Anglo-Saxon Era denotes the period of...

 and other Germanic peoples

Germanic peoples

The Germanic peoples are an Indo-European ethno-linguistic group of Northern European origin, identified by their use of the Indo-European Germanic languages which diversified out of Proto-Germanic during the Pre-Roman Iron Age.Originating about 1800 BCE from the Corded Ware Culture on the North...

. In an extended sense, it then became the standard term for a variety of other kinds of lineal (matrilineal

Matrilineality

Matrilineality is a system in which descent is traced through the mother and maternal ancestors. Matrilineality is also a societal system in which one belongs to one's matriline or mother's lineage, which can involve the inheritance of property and/or titles.A matriline is a line of descent from a...

 or patrilineal

Patrilineality

Patrilineality is a system in which one belongs to one's father's lineage. It generally involves the inheritance of property, names or titles through the male line as well....

) or cognatic (i.e.,descended through links of both sexes) kinship groups

Kinship terminology

Kinship terminology refers to the various systems used in languages to refer to the persons to whom an individual is related through kinship. Different societies classify kinship relations differently and therefore use different systems of kinship terminology - for example some languages...

. The word may also denote a member of such a group.

American anthropologists often used the term 'sib' as the generic term for a category that breaks down into the sub-classifications of patri-sib, referring to patrilineal clan

Clan

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...

descent, and matri-sib, to refer to matrilineal clan descent.