barrier to entry  anything that impedes the ability of firms to begin a new business in an industry in which existing firms are earning positive economic profits
deadweight loss  the reduction of consumer surplus without a corresponding increase in monopoly profit when a perfectly competitive firm is monopolized
local monopoly  a monopoly that exists in a limited geographic area
monopoly  a market structure in which there is a single supplier of a product
monopoly firm (monopolist)  a single supplier of a product for which there are no close substitutes
monopoly power  market power, the ability to set prices
natural monopoly  a monopoly that emerges because of economies of scale
potential competition  possible entry or rivalry capable of forcing existing producers to behave as if the competition actually existed
predatory dumping  dumping to drive competitors out of business
price discrimination  charging different customers different prices for the same product
regulated monopoly  a monopoly firm whose behavior is monitored and prescribed by a government entity
X-inefficiency  the tendency of a firm not faced with competition to become inefficient