<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> A monopoly (from Greek μόνος mónos ("alone" or "single") and πωλεῖν pōleîn ("to sell")) exists when a specific person or enterprise is the only supplier of a particular commodity . This contrasts with a monopsony which relates to a single entity's control of a market to purchase a good or service, and with oligopoly which consists of a few sellers dominating a market . Monopolies are thus characterized by a lack of economic competition to produce the good or service, a lack of viable substitute goods, and the possibility of a high monopoly price well above the seller's marginal cost that leads to a high monopoly profit . The verb monopolise or monopolize refers to the process by which a company gains the ability to raise prices or exclude competitors . In economics, a monopoly is a single seller . In law, a monopoly is a business entity that has significant market power, that is, the power to charge overly high prices . Although monopolies may be big businesses, size is not a characteristic of a monopoly . A small business may still have the power to raise prices in a small industry (or market). </P> <P> A monopoly is distinguished from a monopsony, in which there is only one buyer of a product or service; a monopoly may also have monopsony control of a sector of a market . Likewise, a monopoly should be distinguished from a cartel (a form of oligopoly), in which several providers act together to coordinate services, prices or sale of goods . Monopolies, monopsonies and oligopolies are all situations in which one or a few entities have market power and therefore interact with their customers (monopoly or oligopoly), or suppliers (monopsony) in ways that distort the market . </P>

What do all types of monopolies have in common