Kin Groups and Descent. Every Sio is a member by birth of a patrilineal descent group (lineage). There is no term for "lineage," nor are the various lineages named. Rather they are known by the names of their heads, who tend to be firstborn sons. The lineage is principally a custodial landholding group and rarely assembles as an action group. Male members of the lineage, however, tend to live in residential clusters and frequently combine in gardening associations and for house building and other tasks.
Kinship Terminology. Cousin terms are of the generational or Hawaiian type. Avuncular terms are of the bifurcate-merging or Iroquois type.