Economic sector is each of the branches of production, classified according to their relative characteristics, taking into account above all the way in which the goods or services are produced. The notion appears very early in economic thought, but is not developed until the first half of the century, when Allan Fisher"),[1]​ Colin Clark&action=edit&redlink=1 "Colin Clark (economist) (not yet written)"),[2]​ and Jean Fourastié [3]​ establish the classic division of primary sector, producer of raw materials or unprocessed goods, secondary, linked to the processing of goods obtained by the first sector, that is, industry, and tertiary, related to the services that enable the development of the previous ones directly, transportation, logistics or administration, and indirectly, care of workers, education and legal services, for example.[4]​ Based on the development of new information and communication technologies, as well as the importance of services linked to credit, the so-called quaternary sector has been introduced, related to finance and property, but also with knowledge as an economic asset.[5]​ Some also propose a sector. quinary, made up of activities without direct payment, such as household work, or those that are carried out without profit; recycling services are also included in this sector.[6]​ From another point of view, the quinary sector is considered in a completely different way as services linked to the most concentrated sectors of the economy and administration, for example: high-level management [7]​[8]​.

The classification of goods and services based on the ownership of the means of production is also called the economic sector. In this case there is a private sector, when the owners of companies are part of civil society, individually or shared through shares, and who own them to carry out a commercial activity,[9]​ a public sector, in which the property is in the hands of the State, generally without profit purpose,[10]​ and a third sector, made up of those companies that produce goods or services that do not belong to the State, but are not managed by individuals with a commercial purpose (this is with the aim of profit).[11]​.

The four production sectors can be subdivided, in turn, into partial sectors by activity: