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" as the children of one's uncles and aunts.
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".
The ordinals in the terms "first cousins", "second cousins", "third cousins", refer to the number of generations to one's closest common ancestor. The number of "G" words used to describe this ancestor will determine how close the relationship is. For example, having "great-great-grandparents" in common would be third cousins.
When the cousins are not the same generation, they are described as "removed". In this case, the smaller number of generations to the common ancestor is used to determine the degree, and the difference in generations determines the number of times removed. Note that the ages of the cousins are irrelevant to the definition of the cousin relationship.
A child ("Sam") of one person ("Laura") and a child ("Ryan") of that one person's sibling ("Robert") are first cousins. First cousins share grandparents ("Joseph" and "Nancy").
Sam and Ryan are first cousins because they are non-siblings who share a pair of grandparents.
The children of first cousins share a second cousin relationship. Second cousins share great-grandparents. People occasionally mistake the child of their first cousin as their "second cousin" - however that would actually be a first cousin, once removed. The removal denotes the generational difference.
Sam and Susannah are second cousins because they are non-first cousins and non-siblings who share great-grandparents. In other words, Sam and Susannah's parents are cousins.
The grandchildren of two first cousins; also the children of two second cousins. Third cousins share great-great-grandparents.
Sam and Lyla are third cousins because they are non-second cousins, non-first cousins and non-siblings who share great-great-grandparents.
First cousins once removed
Two people for whom a first cousin relationship is one generation removed. The child of one's first cousin; also the first cousin of one's parent.
Frank and his father's first cousin, Emma, are first cousins once removed.
There exist numerous terms for first cousins once removed that describe the relationship more specifically:
First cousins twice removed
Two people for whom a first cousin relationship is two generations removed. The grandchild of one's first cousin; also the first cousin of one's grandparent.
Harry and his grandfather's first cousin, Emma, are first cousins twice removed.
There exist numerous addition terms to describe the relationship of first cousin twice removed more specifically and accurately:
Second cousins once removed
Two people for whom a second cousin relationship is one generation removed. The child of one's second cousin; also the second cousin of one's parent.
Harry and his father's second cousin, Gloria, are second cousins once removed.
There are more ways in which this type of relationship can be described more specifically:
The following is a list of less common cousin terms.
|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.||David and Irene 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 (Ben and Helen) having married another brother and sister (Hugh and Betty). For David and Irene, 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.|
|Half-cousin||Half-cousins are the children of two half-siblings, and their respective spouses.||David and Lilian are half cousins because their fathers (Ben and James) are maternal half-brothers, their grandmother (Agatha) having remarried.|
|Stepcousin||Stepcousins are either stepchildren of an individual's aunt or uncle or nieces and nephews of one's stepparent.||David and Mary are stepcousins because David's uncle (Charles) has become Mary's stepfather as a result of Mary's mother (Corinda) having remarried.|
|Cousin-in-law||A cousin-in-law is the spouse of an individual's cousin or the cousin of one's spouse.||David and Eric are first cousins-in-law to each other because Eric's wife (Emma) is David's first cousin.|
|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.||Emma and David are paternal first cousins (being related through their fathers). Emma is also Natalia's paternal first cousin (as related on Natalia's father's side), but Natalia is Emma's maternal first cousin (as related on Emma's mother's side). David and Natalia would only be related if they shared a common ancestor.|
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 one person's →||Parent||Grandparent||Great-grandparent||Great-great-grandparent||Great-great-great-grandparent||Great-great-great-great-grandparent|
| Is the other person's
|Then they are ↘|
|Parent||Siblings||Parent/Child or Uncle/Aunt||Grandparent/Grandchild||Great grandparent/Great grandchild||Great great grandparent/Great great grandchild||Great great great grandparent/Great great great grandchild|
|Grandparent||Parent/Child or Uncle/Aunt||1st cousins||1st cousins once removed||1st cousins twice removed|| 1st cousins
|1st cousins 4× removed|
|Great-grandparent||Great-uncle/Great-aunt||1st cousins once removed||2nd cousins||2nd cousins once removed||2nd cousins twice removed|| 2nd cousins
|Great-great-grandparent||Great-great-uncle/Great-great-aunt||1st cousins twice removed||2nd cousins once removed||3rd cousins||3rd cousins once removed||3rd cousins twice removed|
|Great-great-great-grandparent||Great-great-great-uncle/Great-great-great-aunt||1st cousins 3× removed||2nd cousins twice removed||3rd cousins once removed||4th cousins||4th cousins once removed|
|Great-great-great-great-grandparent||Great-great-great-great-uncle/Great-great-great-great-aunt||1st cousins 4× removed||2nd cousins 3× removed||3rd cousins twice removed||4th cousins once removed||5th cousins|
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.
- Collateral descendant
- Cousin marriage
- Parallel and cross cousins
- Second-degree relative
- "Genetic And Quantitative Aspects Of Genealogy – Types Of Collateral Relationships". Genetic-genealogy.co.uk. Retrieved 28 October 2014.
- "What is a First Cousin, Twice Removed?". Genealogy.com. Retrieved Sep 26, 2015.
- "Sibling" would be a more accurate label for this box. Also, read "son|daughter" for "son", and "nephew|niece" for "nephew".
|Look up cousin in Wiktionary, the free dictionary.|
- European kinship system
- Genealogy.com definition of various cousins
- Genealogy.com: What makes a cousin?
- Genetic Genealogy
- Family Relationship Chart