A "nomadic tribal area" is an an area led by tribal leaders or chiefs (stong dpon, rgya dpon, ru dpon) (nomadic areas). They are polities because they held the power of taxation and so forth.   Civil leaders and tribal leaders may have been ultimately subordinate to larger powers, but our working impression is that they truly ruled localities in much of cultural Tibet without significant outside interference, much like the Ganden Podrang did of central Tibet.

In Tibet, there were three primary types of small scale political entities that were larger than simply a single self-sufficient village, but smaller than any broad regional polity formation: agricultural estates, nomadic trival areas, and monastic parishes.