The coefficient of relationship is a measure of the degree of consanguinity (or biological relationship) between two individuals. A coefficient of inbreeding can be calculated for an individual, as a measure for the amount of pedigree collapse within that individual's genealogy. The term coefficient of relationship was defined by Sewall Wright in 1922, and was derived from his definition of the coefficient of inbreeding of 1921. The measure is most commonly used in genetics and genealogy.