A monopoly (from the Greek language monos, one + polein, to sell) is defined as a persistent market situation where there is only one provider of a product or service, in other words a firm that has no competitors in its industry. Monopolies are characterized by a lack of economic competition for the good or service that they provide and a lack of viable substitute goods.
Monopoly should be distinguished from monopsony, in which there is only one buyer of the product or service; monopolies often have monopsony control of a sector of a market. Likewise, monopoly should also be distinguished from the phenomenon of a cartel. In a monopoly a single firm is the sole provider of a product or service; in a cartel a centralized institution is set up to partially coordinate the actions of several independent providers (which is a form of oligopoly).
A government-granted monopoly, or legal monopoly is sanctioned by the state, often to provide a greater reward and incentive to invest in a risky venture. The government may also reserve the venture for itself, which is called a government monopoly.
If a monopoly is not protected from competition by law, then it is subject to competitive forces. However, with enough market share, a company or group can partially plan and control the market through strategic product updates or lower prices - potential competition can be thwarted, while demand for the dominant company's output can be preferentially developed. Hence, within free economies, planned sub-economies can arise.