Definitions for "Civitas"
The basic administrative unit in Roman Britain. They were derived from existing British tribes, and were governed by a council drawn from the local landowners, who used a local town (the civitas capital) as their centre of government.
The name given to a territory occupied by a conquered tribe
the city and surrounding territory served as a basis of the administrative system in the Frankish kingdom. (p. 236)
Keywords:  tribal, unit