Monopoly is a control or advantage obtained by one entity over the commercial market in a specific area. Monopolization is an offense under federal anti trust law. The two elements of monopolization are (1) the power to fix prices and exclude competitors within the relevant market. (2) the willful acquisition or maintenance of that power as distinguished from growth or development as a consequence of a superior product, business acumen or historical accident.

A market condition in which there is only one seller and one buyer is called a bilateral monopoly. A situation where one buyer controls the market is called monopsony.