What is zoning in real estate?

It's a classification that controls the permitted use(s) of property in a particular area. In general, it will limit them to residential (single family and multi-unit dwellings), commercial, industrial, institutional, and agricultural types or extents of use. Usually, there are subsets of each types. The effect is that nothing can be added (or changed) without approval from the zoning authority. In most locations, there is an over-riding Official Plan that divides the relevant municaplity into its zones.