A more thorough explanation:

EXTRA COMMERCIUM

Extra commercium (eks-trə kə-mər-shee-əm) is a Latin phrase that means "outside commerce." In Roman and civil law, it refers to property that is dedicated to public use and is not subject to private ownership.

• Public parks
• Streets and sidewalks
• Government buildings

These examples illustrate the definition of extra commercium because they are all dedicated to public use and are not owned by any individual or private entity. Public parks, for instance, are open to everyone and are maintained by the government for the benefit of the community. Similarly, streets and sidewalks are public spaces that are used by everyone and are maintained by the government. Government buildings, such as courthouses and city halls, are also dedicated to public use and are not owned by any individual or private entity.