The terms commons originates from Thomas Moore, who describes how the commons are bing taken away by fences and private property. In here a common is referred to Open Grounds, fields that are shared among everyone, a group of people or communities. A common is a good that is shared collectively and not owned privately. It is excluded from private ownership.
"Commons" refers to a particular institutional form of structuring the rights to access, use, and control resources. (...) The salient characteristic of commons, as opposed to property, is that no single person has exclusive control over the use and disposition of any particular resource in the commons. Instead, resources governed by commons may be used or disposed of by anyone among some (more or less well-defined) number of persons, under rules that may range from "anything goes" to quite crisply articulated formal rules that are effectively enforced. ref