Cousin

For other uses, see Cousin (disambiguation).

"Cousins" redirects here. For other uses, see Cousins (disambiguation).

A cousin is a relative with whom a person shares one or more common ancestors. In the general sense, cousins are two or more generations away from any common ancestor, thus distinguishing a cousin from an ancestor, descendant, sibling, aunt, uncle, niece, or nephew. However in common parlance "cousins" typically refers to "first cousins", individuals who share a grandparent.

Systems of "degrees" and "removals" are used in the English-speaking world to describe the exact relationship between two cousins (in the broad sense) and the ancestor they have in common. Various governmental entities have established systems for legal use that can precisely specify kinships with common ancestors existing any number of generations in the past, though common usage often eliminates the degrees and removals and refers to people with common ancestry as simply "distant cousins" or "relatives".

Basic definitions

"First cousin once removed" redirects here. For the documentary film, see First Cousin Once Removed.

People are related with a type of cousin relationship if they share a common ancestor and the most recent common ancestor is more than two generations apart for both people. This means neither person is an ancestor of the other (descendants and ancestors), they do not share a parent (siblings), and neither is a sibling of a common ancestor (aunts/uncles and nieces/nephews).

The cousin relationship is further detailed by degree and removal. For example the second cousin once removed relationship is a second degree cousin with one removal.

The removal of the cousin relationship is the number of generations the cousins are apart. When the number of generations the cousins have to go back before finding the same most recent common ancestor is different, the cousin relationship is said to be removed. The difference between the number of generations is the removal. For example if one person's grandfather is the other person's great-grandfather or one person's great-grandfather is the other person's great-great-grandfather the cousins are once removed. Note that two people can be removed but be around the same age due to differences in birth dates of parents children and other relevant ancestors.

The degree of the cousin relationship is the number of generations prior to the parents before a most recent common ancestor is found. If the cousins are removed, the smaller number of generations to the most recent common ancestor is used to determine the degree of the cousin relationship. For example if one of the cousins has to go back one generation beyond their parents (the grandparents) before finding the most recent common ancestor and the other has to go back one or more they are first cousins. If one had to go back two generations beyond the parents (great grandparents) and the other had to go back two or more they would be second cousins.

Examples

Example family tree
Jason Beatrice James Helen Eugene Mary Nancy Joseph Julie Roger Gordon Laura Christina Matt Sam Lyla

• First cousins

A person shares a first cousin or cousin relationship with the children of their parents siblings. Cousins share least one set of grandparents. In the example to the right Joseph and Julie are first cousins.

• Second cousins

A person shares a second cousin relationship with the children of their parents cousins. Second cousins share at least one set of great-grandparents. In the example to the right Gordon and Matt are second cousins.

• Third cousins

A person shares a third cousin relationship with the children of their parents second cousins. Third cousins share at least one set of great-great-grandparents. In the example to the right Sam and Lyla are third cousins.

• First cousins once removed

A person shares a first cousins once removed relationship with their parents cousins and their cousins children. At least one set of one person's grandparents are the great-grandparents of the other person. In the example to the right Gordon and Julie, as well as Joseph and Matt are first cousins once removed.

• First cousins twice removed

A person shares a first cousins twice removed relationship with their grandparents cousins and their cousins grandchildren. At least one set of one person's grandparents are the great-great-great-grandparents of the other person. In the example to the right Sam and Julie, as well as Joseph and Lyla are first cousins twice removed.

• Second cousins once removed

A person shares a second cousin once removed relationship with their parents second cousins and their second cousins children. At least one set of one person's great-grandparents are the great-great-grandparents of the other person. In the example to the right Sam and Matt, as well as Gordon and Lyla are second cousins once removed.

Relationship charts

Cousin chart

A "cousin chart", or "table of consanguinity", is helpful in identifying the degree of cousin relationship between two people using their most recent common ancestor as the reference point. Cousinship between two people can be specifically described in degrees and removals by determining how close, generationally, the common ancestor is to each person.

If your →		Parent	Grandparent	Great-grandparent	Great-great-grandparent	Great-great-great-grandparent	Great-great-great-great-grandparent
Is the other person's ↓	Then you are the other person's ↘
Parent		Sibling	Nibling	Grandnibling	Great-grandnibling	Great-great-grandnibling	Great-great-great-grandnibling
Grandparent		Uncle/​Aunt	1st cousins	1st cousins once removed	1st cousins twice removed	1st cousins thrice removed	1st cousins 4× removed
Great-grandparent		Granduncle/​Grandaunt	1st cousins once removed	2nd cousins	2nd cousins once removed	2nd cousins twice removed	2nd cousins thrice removed
Great-great-grandparent		Great-granduncle/​Great-grandaunt	1st cousins twice removed	2nd cousins once removed	3rd cousins	3rd cousins once removed	3rd cousins twice removed
Great-great-great-grandparent		Great-great-granduncle/​Great-great-grandaunt	1st cousins thrice removed	2nd cousins twice removed	3rd cousins once removed	4th cousins	4th cousins once removed
Great-great-great-great-grandparent		Great-great-great-granduncle/​Great-great-great-grandaunt	1st cousins 4× removed	2nd cousins thrice removed	3rd cousins twice removed	4th cousins once removed	5th cousins

Canon law relationship chart

Canon Law Relationship Chart. See an example of how to use chart.

Another visual chart used in determining the legal relationship between two people who share a common ancestor is based upon a rhombus shape, usually referred to as a "canon law relationship chart".

The chart is used by placing the "common progenitor" (the most recent person from whom both people (A and B) are descended) in the top space in the diamond-shaped chart, and assigning a direction (arbitrarily, left or right) to each of the two people, A and B. Then follow the line down the outside edge of the chart for each of the two people until their respective relationship to the common ancestor is reached. Upon determining that place along the opposing outside edge for each person, their relationship is then determined by following the lines inward to the point of intersection. The information contained in the common "intersection" defines the relationship.

For a simple example, in the illustration to the right, if two siblings use the chart to determine their relationship, their common parent (either one, if there are two) is placed in the topmost position, and each child is assigned the space below and along the outside of the chart. Then, following the spaces inward, they would intersect in the "brother" diamond. If their children want to determine their relationship, they would follow the path established by their parents but descend an additional step below along the outside of the chart (showing that they are grandchildren of the common progenitor); following their respective lines inward, they would come to rest in the space marked "1st cousin". In cases where one side descends the outside of the diamond further than the other side because of additional generations removed from the common progenitor, following the lines inward shows both the cousin rank (1st cousin, 2nd cousin) plus the number of times (generations) "removed".

In the example provided at the right, generations one (child) through ten (8th great-grandchild) from the common progenitor are provided; however, the format of the chart can easily be expanded to accommodate any number of generations needed to resolve the question of relationship.

Additional terms

The following is a list of less common cousin terms.

Term	Definition	Example	Chart
Double cousin	Double cousins arise when two siblings of one family mate with two siblings of another family. The resulting children are related to each other through both of their parents and are thus doubly related. Double first cousins share both sets of grandparents and have twice the degree of consanguinity of ordinary first cousins; genetically, they are as related as half-siblings. In a scenario where two monozygotic (identical) twins mate with another pair of monozygotic twins, the resulting double cousins would test as genetically similar as brothers or sisters. Double second cousins can arise in two ways: from the relationships of two first-cousins with two other first-cousins or from the relationships two double-first-cousins with two other persons. May also be known as 'Cousins on both sides.'	Joseph and Julie are double first cousins because each is related through their mother's family and also their father's family, the result of a brother and sister (Helen and Eugene) having married another brother and sister (James and Mary). For Joseph and Julie, each has a mother who is an aunt by blood of the other and a father who is an uncle by blood of the other.	Gary Glenda Jason Beatrice James Helen Eugene Mary Joseph Julie
Half-cousin	Half-cousins are the children of two half-siblings, and their respective spouses.	Joseph and Lilian are half cousins because their parents (Helen and Charles) are half-siblings, their grandmother (Beatrice) having remarried.	Jason Beatrice Anthony James Helen Charles Janet Joseph Lilian
Stepcousin	Stepcousins are either stepchildren of an individual's aunt or uncle or nieces and nephews of one's stepparent.	Joseph and Rachel are stepcousins because Joseph's uncle (Eugene) has become Rachel's stepfather as a result of Rachel's mother (Corinda) having remarried Eugene.	Jason Beatrice James Helen Eugene Corinda Colin Joseph Rachel
Cousin-in-law	A cousin-in-law is the spouse of an individual's cousin or the cousin of one's spouse.	Joseph and Roger are first cousins-in-law to each other because Roger's wife (Julie) is Joseph's first cousin.	Jason Beatrice James Helen Eugene Mary Joseph Julie Roger
Maternal or paternal cousin	A term that specifies whether one individual is a cousin of another through the mother's side of the family (maternal) or the father's side (paternal). If the relationship is not equally paternal for both or equally maternal for both, then the paternal cousin of one is the maternal cousin of the other.	Julie and Natalia are maternal first cousins (being related through their mothers). Julie is also Joseph's maternal first cousin (as related on Joseph's mother's side), but Joseph is Julie's paternal first cousin (as related on Julie's fathers's side). Joseph and Natalia would only be related if they shared a common ancestor.	Jason Beatrice Gary Glenda James Helen Eugene Mary Maud Mark Joseph Julie Natalia

See also

• Collateral descendant
• Consanguinity
• Cousin marriage
• Family
• Parallel and cross cousins
• Sibling
• Second-degree relative

External links

• European kinship system
• Genealogy.com definition of various cousins
• Genealogy.com: What makes a cousin?
• Genetic Genealogy
• Family Relationship Chart