Australian Aboriginal kinship
Aboriginal Australian kinship comprises the systems of Aboriginal customary law governing social interaction relating to kinship in traditional Aboriginal cultures. It is an integral part of the culture of every Aboriginal group across Australia, and particularly important with regard to marriages between Aboriginal people. The subsection system. Subsection systems are a unique social structure that divide all of Australian Aboriginal society into a number of groups, each of which combines particular sets of kin. In Central Australian Aboriginal English vernacular, subsections are widely known as "skins". Each subsection is given a name that can be used to  refer to individual members of that group. Skin is passed down by a person's parents to their children. The name of the groups can vary. There are systems with two such groupings (these are known as 'moieties' in kinship studies), systems with four (sections), six and eight (subsection systems). Some language groups extend this by having distinct male and female forms, giving a total of sixteen skin names, for example the Pintupi (listed below) and Warlpiri. While membership in skin groups is ideally based on blood relations, Australian Aboriginal subsection systems are classificatory, meaning that even people who are  not actual blood relations are assigned to a subsection. They are also universal, meaning that every member of the society is assigned a position in the system. Subsection systems are found in Aboriginal societies across much of Central, Western and Northern Australia. On the basis of detailed analysis and comparison of the various subsection systems and their terminologies, and in particular the apparent prefix /j-/ for male and /n-/ for female, it has been identified as a social innovation originally from the Daly River region of the Northern Territory, which then spread rapidly southwards to other groups. Systems with two  groupings (moieties). Yolngu. The Yolŋu people of north-eastern Arnhem Land divide society (and much of the natural world) into two moieties: "Dhuwa" and "Yirritja". Each of these is represented by people of a number of different groups (each with their own lands, languages and philosophies) through their hereditary estates – so many things are either "Yirritja" or "Dhuwa": Fish, stone, river, sea etc., belongs to one or the other moiety. Things that are not either Dhuwa or Yirritja are called "wakinŋu". Yolŋu also have a kinship system with eight subsections (four Dhuwa and four Yirritja which is what creates moiety ). Systems with four sections. Gamilaraay. The Gamilaraay language group from New South Wales have a four-section system. Martuthunira. The Martuthunira language group from the Pilbara region of Western Australia have a four-section system. (The spelling l.y indicates that the letters represent two distinct phonemes, and are not a digraph). Similar systems are found across most language groups in the Pilbara, though with some variation in the forms of the names. For example, speakers of Ngarla use "Milangka" where Martuthunira use "Pal.yarri". Alyawarra. The Alyawarre language group from Central Australia also have a four-section system, but use different  terms from the Martuthunira. Systems with eight groups (subsection systems). Lardil. The Lardil of Mornington Island in the Gulf of Carpentaria have eight subsection groups, shown here with some of their totems: Each Lardil person belongs to one of these groups. Their paternal grandfather's subsection determines their own; so a Balyarriny man or woman will have a Balyarriny grandfather. Members of each group may only marry members of one other, specified, group. Once a person's subsection group is known, their relationship to any other Lardil can be determined. A Ngarrijbalangi is a 'father' to a Bangariny, a 'father -in-law' to a Yakimarr and a 'son' to another Bangariny, either in a social sense or purely through linearship. The mechanics of the Lardil skin system means that generations of males cycle back and forth between two subsections. "Ngarrijbalangi" is father to "Bangariny" and "Bangariny" is father to "Ngarrijbalangi" and similarly for the three other pairs of subsections. Generations of women, however, cycle through four subsections before arriving back at the starting point. This means that a woman has the same subsection name as her (matrilineal) great-great-grandmother. Pintupi. The Pintupi of the Western Desert also have an  eight-subsection system, made more complex by distinct forms for male and female subsection names; male forms begin with "Tj", the female forms with "N". The Warlpiri system is almost the same: Kunwinjku. The Kunwinjku of Western Arnhem Land have a similar system; male forms begin with "Na", the female forms with "Ngal": Each person therefore has a patrimoiety and a matrimoiety, a father's and a mother's subsection group. Extension of the system to non-relatives. Outsiders who have significant interaction with such groups may be given a 'skin name', commonly based on the people they have interacted  with and the types of interaction. Some common kinship terms used in Aboriginal English. The variety of English used by many Australian Aboriginal people employs kinship terms in ways that are based on their equivalents in Australian Aboriginal languages.