How are a niece from one sister and a niece from another sister related in what way?

This article reflects the long-standing use of the term kinship in anthropology, which refers to the web of social relationships that form an important part of the lives of most humans in most societies, although its exact meanings even within this discipline are often debated. Anthropologist Robin Fox states that "the study of kinship is the study of what man does with these basic facts of life - mating, gestation, parenthood, socialization, siblingship etc." Human society is unique, he argues, in that we "are working with the same raw material as exists in the animal world, but [we] can conceptualize and categorize it to serve social ends." These social ends include the socialization of children, and the formation of basic economic, political, and religious groups.

Within anthropology, kinship can refer both to the patterns of social relationships themselves, or it can refer to the study of the patterns of social relationships in one or more human cultures (i.e. kinship studies). Over its history, anthropology has developed a number of related concepts and terms in the study of kinship, such as descent, descent group, lineage, affine, cognate and fictive kinship. Further, even within these two broad usages of the term, there are different theoretical approaches.

A nephew is a son of one's sibling or half-sibling, and a niece is a daughter of one's sibling or half-sibling. Sons and daughters of siblings-in-law are also informally referred to as nephews and nieces respectively, even though there is no blood relation. The word nephew is derived from the French word neveu.

In some cultures and family traditions, it is common to refer to one's first cousin once removed (the child of one's cousin), as a niece or nephew. In archaic terminology, a maternal nephew is called a sister-son, emphasizing the importance as a person's nearest male relative should he have no brothers or sons of his own. The term is used to describe some knights who are nephews to King Arthur and is imitated by J. R. R. Tolkien, especially in lists of Kings of Rohan or dwarves where the sister-son is also heir. Sister-daughter is a less common parallel term for niece.

Elizabeth Murray Campbell Smith Inman (July 7, 1726 – May 25, 1785) was a shopkeeper, teacher, philanthropist, and proto-feminist in Boston, Massachusetts, before, during, and after the American Revolution. Elizabeth spent much of her adult life teaching her nieces and female friends the importance of personal financial autonomy through shopkeeping and other traditionally female domestic duties.