A part of the economy. Sectors can be delimited in a number of different ways. One way is by the bodies organizing expenditures: thus the economy is divided between the public sector, that is, the government at various levels and government-controlled bodies; the corporate sector, which is companies; and the personal sector, which is individuals, and unincorporated businesses. For national income accounting purposes the rest of the world is sometimes regarded as a sector. Sectors may also be distinguished by the type of product: a primary sector, that is, agriculture and mining; a secondary, or manufacturing, sector; and a tertiary, or services, sector. See also industrial sector; organized sector; sensitive sectors.
Reference: Oxford Press Dictonary of Economics, 5th edt.