This is a collection of commons definitions.
"There is no commons without commoning." (attributed to Peter Linebaugh: Zitate)
"commons is the social form of (tangible and/or intangible) matter that is determined by commoning. Hence, a matter only becomes a commons if people predominantly relate to it by commoning and if, therewith, the social form is determined by these very practices." (Euler 2017)
...in response to this question by a member of the CommonsWatch email list: "I desperately need a concise and plain english definition of commons and everything I find is super wordy, complex, academic and not understandable by those not in the field." Julien Lecaille: "A group of people managing something useful for themselves and others, with transparent discussions about this management, without thinking themselves as the only owners and without necessarily turning a profit out of it"
# Stephen Gudeman "The commons is a shared interest or value. It is the patrimony or legacy of a community and refers to anything that contributes to the material and social sustenance of a people with a shared identity: land, buildings, seed stock, knowledge of practices, a transportation network, an educational system, or rituals. As the lasting core, though changeable over time, the base represents temporality and continuity. Without a commons, there is no community; without a community, there is no commons."
# Kenneth R. Olwig "The commons is the material landscape of common lands shared by a community of commonres with customary use rights in the land." (2013:31), pdf