Final answer:
In tribes, the non-kinship based groupings that sometimes compete with lineage are known as age sets or age grades, which organize individuals based on age rather than family ties.
Step-by-step explanation:
In tribes, non-kinship based groupings that can sometimes compete with lineage are referred to as age sets or age grades. These social structures are organized not by direct family ties but by the age of their members, often forming cohorts of individuals born within a certain time span. These groups may provide social support, help induct young members into adulthood, and assign responsibilities that are independent of family lineage. They can be significant factors in tribal organization, governance, and social life, adding another layer of complexity beyond kin-based networks.
For example, among the Nuer of South Sudan, maximal lineages and clans are part of a broader kinship network involving descent from common ancestors. Contrarily, age sets and age grades provide alternative means to form bonds, create social cohesion and resolve conflicts beyond the direct kinship lines. Similarly, among the Cherokee, matrilineality dictates kinship; however, such societies may also employ non-kinship structures for decision-making and social organization.