Cooperative
The Wikipedia has a very elaborate entry on Cooperatives.
See at http://en.wikipedia.org/wiki/Cooperative
Definition
"A cooperative (also co-operative or co-op) has been defined as "an autonomous association of persons united voluntarily to meet their common economic, social, and cultural needs and aspirations through a jointly-owned and democratically-controlled enterprise." (http://en.wikipedia.org/wiki/Cooperative)