Formally organized social group consisting of every male (or female) of comparable age.
In societies where the practice traditionally occurs (e.g., the Nuer of the southern Sudan or the Masai of Kenya and Tanzania), a person belongs, either from birth or from a determined age, to a named age set that passes through a series of life stages, or age grades, each of which has a distinctive status or social and political role. See also rite of social status .