cousins

   English, like most languages, has a procedure for stating the precise relationship between persons of common descent; a typical designation is "second cousins, once removed." First cousins are persons sharing a common grandparent; second cousins are persons sharing a common great-grandparent, and, generally, for n > 1, n-th cousins are persons sharing a common (n - 1)-times-great-grandparent. This means n-th cousins have n + 1 generations in each of their descents from the common ancestor. The "removed" phrase is used when the number of generations in the descent from the common ancestor is not the same for both cousins: "r times removed" means the difference in the number of generations is r. Thus, for n-th cousins r times removed, the common ancestor is an (n - 1)-times-great-grandparent of one cousin and an (n + r - 1)-times-great-grandparent of the other cousin. (In the case of first cousins r times removed, the grandparent of one cousin is also an r-times-great-grandparent of the other cousin.)

   For n-th cousins r times removed, there are n + 1 generations in the descent from a common ancestor for one cousin, and n + r + 1 generations for the other. The number of degrees of consanguinity between n-th cousins r times removed is 2n + r + 2.