Most Western societies employ Eskimo kinship terminology. This kinship terminology commonly occurs in societies based on conjugal (or nuclear) families, where nuclear families have a degree of relative mobility. Members of the nuclear use descriptive kinship terms:
* Mother: a female parent
* Father: a male parent
* Son: a male child of the parent(s)
* Daughter: a female child of the parent(s)
* Brother: a male child of the same parent(s)
* Sister: a female child of the same parent(s)
* Grandfather: father of a father or mother
* Grandmother: mother of a mother or father
* Cousins: two people that share the same grandparent(s)
An infant, his mother, his maternal grandmother, and his great-grandmother.
Such systems generally assume that the mother's husband has also served as the biological father. In some families, a woman may have children with more than one man or a man may have children with more than one woman. The system refers to a child who shares only one parent with another child as a "half-brother" or "half-sister." For children who do not share biological or adoptive parents in common, English-speakers use the term "stepbrother" or "stepsister" to refer to their new relationship with each other when one of their biological parents marries one of the other child's biological parents. Any person (other than the biological parent of a child) who marries the parent of that child becomes the "stepparent" of the child, either the "stepmother" or "stepfather." The same terms generally apply to children adopted into a family as to children born into the family.
Typically, societies with conjugal families also favor neolocal residence; thus upon marriage a person separates from the nuclear family of their childhood (family of orientation) and forms a new nuclear family (family of procreation). However, in the western society the single parent family has been growing more accepted and has begun to truly make an impact on culture. The majority of single parent families are more commonly single mother families than single father. These families face many difficult issues besides the fact that they have to rear their children on their own, but also have to deal with issues related to low income. Many single parents struggle with low incomes and must cope with other issues, including rent, child care, and other necessities required in maintaining a healthy and safe home. Members of the nuclear families of members of one's own (former) nuclear family may class as lineal or as collateral. Kin who regard them as lineal refer to them in terms that build on the terms used within the nuclear family:
* Grandparent
o Grandfather: a parent's father
o Grandmother: a parent's mother
* Grandson: a child's son
* Granddaughter: a child's daughter
For collateral relatives, more classificatory terms come into play, terms that do not build on the terms used within the nuclear family:
* Uncle: father's brother, mother's brother, father's sister's husband, mother's sister's husband
* Aunt: father's sister, mother's sister, father's brother's wife, mother's brother's wife
* Nephew: sister's son, brother's son, wife's brother's son, wife's sister's son, husband's brother's son, husband's sister's son
* Niece: sister's daughter, brother's daughter, wife's brother's daughter, wife's sister's daughter, husband's brother's daughter, husband's sister's daughter
When additional generations intervene (in other words, when one's collateral relatives belong to the same generation as one's grandparents or grandchildren), the prefixes "great-" or "grand-" modifies these terms. Also, as with grandparents and grandchildren, as more generations intervene the prefix becomes "great-grand-," adding an additional "great-" for each additional generation. Most collateral relatives have never had membership of the nuclear family of the members of one's own nuclear family.
* Cousin: the most classificatory term; the children of aunts or uncles. One can further distinguish cousins by degrees of collaterality and by generation. Two persons of the same generation who share a grandparent count as "first cousins" (one degree of collaterality); if they share a great-grandparent they count as "second cousins" (two degrees of collaterality) and so on. If two persons share an ancestor, one as a grandchild and the other as a great-grandchild of that individual, then the two descendants class as "first cousins once removed" (removed by one generation); if they shared ancestor figures as the grandparent of one individual and the great-great-grandparent of the other, the individuals class as "first cousins twice removed" (removed by two generations), and so on. Similarly, if they shared ancestor figures as the great-grandparent of one person and the great-great-grandparent of the other, the individuals class as "second cousins once removed". Hence one can refer to a "third cousin once removed upwards."
Cousins of an older generation (in other words, one's parents' first cousins), although technically first cousins once removed, are often classified with "aunts" and "uncles." Similarly, a person may refer to close friends of one's parents as "aunt" or "uncle," or may refer to close friends as "brother" or "sister," using the practice of fictive kinship. English-speakers mark relationships by marriage (except for wife/husband) with the tag "-in-law." The mother and father of one's spouse become one's mother-in-law and father-in-law; the female spouse of one's child becomes one's daughter-in-law and the male spouse of one's child becomes one's son-in-law. The term "sister-in-law" refers to three essentially different relationships, either the wife of one's sibling, or the sister of one's spouse, or, in some uses, the wife of one's spouse's sibling. "Brother-in-law" expresses a similar ambiguity. No special terms exist for the rest of one's spouse's family. The terms "half-brother" and "half-sister" indicate siblings who share only one biological or adoptive parent.
