Community := this is the set of people (cf. human being) living within a geographical area (defined by the community confines) and this geographical area and the atmosphere above the surface.
As can be seen, the definition is analogous to that of the term state. Hence, the state is a community, i.e. the top-most community encompassing all sub-communities.
Communities range from the smallest so-called basic communities, over regions and quarters to the entire state.
A basic community has 40 to 280 grownup citizens (parameters: p_c_minimum_citizens_in_basic_community and p_c_maximum_citizens_in_basic_community). It is governed by 7 representative couples, each responsible for 1 of the 7 domains. Also, each basic community must contain at least 14 marriages (c.f. Persons administration, parameter: p_c_minimum_marriages_in_basic_community). If this is not achieved within the maximum of 280 grownup citizens, then this limit can (must) be exceeded.
A higher-order community is composed of 5 to 11 basic communities or higher order communities which are then referred to as the direct sub-communities of the higher-order community (parameters: p_c_minimum_sub_communities_in_higher_order_community and p_c_maximum_sub_communities_in_higher_order_community). Also, we say that a higher-order community contains the sub-communities.
The order of a community is the distance to the basic communities, i.e. 0 for the basic communities, 1 for the community bundling basic communities, 2 for the next, etc.
When the order of a community is 2 or higher, then of the direct sub-communities all contained further sub-communities until down to the basic communities are called indirect sub-communities. And the direct + indirect sub-communities are just referred to as the sub-communities.
Communities up to order 2 must be geographically coherent with the thinnest part being 50 meters, i.e. no small exclaves or inclaves are allowed (parameters: p_c_maximum_community_order_mandatory_coherent and p_c_minimum_meters_of_thinnest_part_of_coherent_community). Larger communities are allowed to be geographically non-coherent (e.g. Alaska, Finland and Greenland might form a state or community - a purely ficitve example).
The built-vs-free-land-ratio of a community is the total built-over surface (buildings without the garden, streets/parking lots/paved or gravelled paths/roads/places, railway tracks) versus the total surface, excl. open water, of the community.
A higher order community with 30'000 or more grownup citizens and a built-vs-free-land-ratio of 10% or lower may call itself a region (parameters: p_c_minimum_citizens_in_region and p_c_maximum_built-vs-free-land-ratio_in_region). If the built-vs-free-land-ration is greater than 10%, then it may call itself a quarter or suburb or city.