Market situation with a single supplier (monopolist) who — due to the absence of competition — holds an extreme form of market power. It is tantamount to the existence of a dominant position. Under monopoly, output is normally lower and price higher than under competitive conditions. A monopolist may also be deemed to earn supra-normal profits (that is, profits that exceed the normal remuneration of the capital). A similar situation on the demand side of the market, which is with a single buyer only, is called monopsony.
Source: Glossary of terms used in EU competition policy, Antitrust and control of concentrations, European Commission, 2002