What zoning term describes a district created in a zoning ordinance but not mapped?

The correct choice refers to "Floating Zones," which are a unique zoning term applied within urban planning and zoning practices. These zones are established by a zoning ordinance but do not have a specific location mapped out on the official zoning map. Instead, the purpose of floating zones is to allow flexible development within designated areas that meet the criteria outlined in the zoning ordinance when a developer applies for a project. This means that while the regulations exist and prescribe the intended uses, the area where the floating zone can be applied may vary, thus "floating" over potential locations until a development project is proposed.

In contrast, overlay zones are additional regulations that apply to specific geographic areas already designated on a zoning map, and buffer zones typically refer to areas meant to separate different zones to minimize conflict (like between residential and commercial areas). Exclusion zones relate to areas where certain types of development are explicitly prohibited. The distinction of floating zones as versatile and non-specific until activated by a specific project is what makes them the correct answer in this context.