An accessory building is best defined as?

An accessory building is most accurately defined as an activity or structure that is incidental and subordinate to the main use of a site. This definition emphasizes that an accessory building typically serves a supportive role to the primary structure, enhancing its functionality without overshadowing it. For example, in a residential setting, a garage, shed, or workshop could be considered accessory buildings, as they provide additional utility but are not the main focus of the property.

In this context, the key characteristics of an accessory building are its secondary nature and its dependence on the primary use of the site. Such buildings often must adhere to specific zoning regulations, ensuring they do not exceed certain size limits or intrude upon the ambiance and utility of the main building.

The other options describe structures that do not fit the definition of an accessory building. For instance, a main structure with multiple uses or a primary residence does not serve as a subordinate facility. Similarly, a commercial establishment on residential land represents a different classification of use that does not align with the concept of accessory structures, which are intended to complement rather than replace the primary activity on a property.