Zoning districts around the USA are mainly divided in three main areas: the commercial, manufacturing or residence district. Another zones are the mixed use district and the special purpose district. Each area has its own regulations and goals, in line with the surrounding neighbourhoods or cities. For example, the residence district is zoned for residential purposes and contains different housing units, while manufacturing districts can allow both commercial and manufacturing planning.
Also, the zoned manufacturing districts (M1, M2, and M3) can allow industrial uses and most commercial uses. Good to keep in mind is that every manufacturing district has different performing standards which can limit the industrial use. For instance, most manufacturing districts allow light manufacturing uses, but limits noxious uses. Industrial uses should also follow the regulations of each city, state or country.
Manufacturing districts generally allow commercial uses such as shops and offices, but one can also think of hotels and entertainment hubs. If the City Planning Commission allows, retail uses can be allowed in the M1 district. M2 and M3 are more strict zones which do not allow retail uses and hotels or guest houses. Community facilities like schools, parks, libraries, sports centers are forbidden in M2 and M3 zones, but they can be allowed in a M1 zone after a special permit has been given.
The ratio of the total area of a building in the manufacturing district, compared to the size of the given land, is measured by use of the Floor Area Ratio (FAR). (NYC City Planning)