There are three basic functions of culturally defined kinship ties and socially recognized kinship categories in all human societies.
Kinship provides continuity between the generations. Socialization of child and initial child care is done in a kinship unit. The transference of property and social positions from one generation to the other takes place in kin groups.
Kinship defines a universe of persons on whom to depend in normal routine of life. The other kin bigger than family are significant in many societies having adaptiveness to different situations. In tribal societies particularly in stateless societies lacking political mechanism to maintain order and initiate other activities the kinship provides the main structure of social action.
Kinship regulates marriage by defining who can marry whom or who should not marry among themselves and extends the area of kinship to unrelated ones through the bonds of marriage.
In small societies, kinship is the most important social bond. Most of the social groups are organized on the basis of kinship. Relationship between the individuals is mainly governed by the kinship norms.
In western societies other principles of social organization such as work, citizenship, common economic and political interest and other varied common interests operate as basis of group organizations. Nuclear family is one of the kin group.
Kinship terminology is the classification of kinship in a society. A kinship term is a term of language used for designating or referring as kin. On the basis of his observation in North American Indian societies, Morgan as early as 19th century talked about two systems of terminology and called them classificatory and descriptive systems of terminology. Morgan observed that in some of the societies people use same term of calling for more than one type of kin which he called as classificatory system of terminology as more than one type of kins are classified by one single term. Similarly of age, group, sex and same generation are usually the basis for such categorization.
In societies where most of the terms of calling are separate terms to. Designate one single kin, the system may be called as the descriptive system of terminology. Morgan saw evolutionary pattern in this type of categorization of societies. He thought that classificatory system was characteristic of primitive societies while the descriptive system was characteristic of modern societies. Under the classificatory system, several kins lineals as well as collaterals and even affinial kins are all referred to by the same term of designation whereas a descriptive term of designation describes one’s exact relation whom he or she is addressing.
WHR Rivers maintained that the kinship terms refer to social usages, certain marriage customs and practices which are antecedent to their use. At times certain kinship terms prevail but the related customs and practices which brought them in use may not exist and may be vanished kinship usages. Thus, their continued usage makes one to correlate them with some of the past practices one can see through the past through them which is particularly of great significance in the context of primitive society lacking any tangible evidence of their past history. Anthropologists like Kroeber held the view that these kinship terms are no more than mechanism of identification and distinction of various kins by just providing a word to name them and that it is futile to read between the lines. According to Kroeber the question of using terms is related to the type of language having an elaborate or limited stock of words. British anthropologist Radcliff- Brown studied the kinship system of Australian aborigines which was highly complex system. It was from this study later on the African kinship systems, a collection of African kinship studies brought certain new insights on the study of kinship terminology. Rejecting any preconceived evolutionary bias or conjecturing about the origin he stressed upon the need to study kinship system functionally from the synchronic point of view. He felt that in studying the kinship system of people , a study of kinship terminology should be the first step. Radcliff Brown also made certain generalizations and called them as principles of kinship structure
Principle of inequality of proximate generations
Principle of the unity of sibling groups maintained by exogamy.