Cousin

A cousin is a relative that is the child of a parent's sibling; this is more specifically referred to as a first cousin.

More generally, in the kinship system used in the English-speaking world, a cousin is a type of relationship in which relatives are two or more generations away from their most recent common ancestor. For this definition Degrees and removals are used to further specify the relationship.

Degree measures the number of generations from the most recent common ancestor(s) to a parent of the cousin. If the cousins do not come from the same generation Removal is specified as removal measures the difference in generations between the two cousins. This is relative to the most recent common ancestor(s). When removal is specified each cousin is separated by a different number of generations from the common ancestor. In this case the degree of the cousin from the previous generation is used.

To illustrate usage, a second cousin is a cousin with a degree of two; there are three (not two) generations from the common ancestor(s). When the degree is not specified, first cousin is assumed. A cousin "once removed" is a cousin with one removal, or generational difference, namely the child of one’s first cousin or the first cousin of one’s parent. When the removal is not specified, no removal is assumed.

Various governmental entities have established systems for legal use that can precisely specify kinship with common ancestors any number of generations in the past; for example, in medicine and in law, a first cousin is a type of third-degree relative.