Material Form of the Commons
“The word „common“ is the best starting point for the analysis. The common thing within a commons are the resources, which are used and cared for, are the goods resulting from joint activities, and are the social relationships emerging from acting together. These three aspects are so different for all commons, that no one could describe them in a reasonably complete manner.
I decide to put the concept of „good“ into the center, while describing from the triple definition explained above: as a common good, as a resource and as a social form.
In the adjoining illustration a good is designated by five dimensions. Beside the already mentioned dimensions resource and social form, there are constitution, usage and legal form." (http://www.keimform.de/2010/01/11/commons-in-a-taxonomy-of-goods/)
See also: Usage Form of the Commons