1. Especially in city planning: of or pertaining to the division of an area into zones, so as to restrict the number and types of buildings and their uses: zoning laws.
2. The laws dividing cities into different areas according to use, from single-family residences to industrial plants. Zoning ordinances control the size, location, and use of buildings within these different areas.
3. Dividing an area into zones or sections reserved for different purposes; such as, residence, business, manufacturing, etc.
4. The occurrence of a stronger reaction in a lesser amount of suspected serum, observed sometimes in serologic tests used in the diagnosis of syphilis, and probably the result of high antibody titre (quantity of a substance required to produce a reaction).