How is a monopoly defined in market structure?

A monopoly is best defined as a scenario where a single seller controls supply. In this market structure, one firm dominates the market, meaning it is the only provider of a particular product or service. This level of control allows the monopoly to set prices and output levels without concern for competition, leading to unique characteristics in terms of market power and pricing strategies.

When a single seller controls supply, they can influence market conditions significantly, often resulting in higher prices and reduced availability of goods compared to a competitive market where multiple sellers exist. This lack of competition means consumers have fewer choices and the monopolist can maximize profits due to the absence of competitive pressures.

In contrast, a market with many sellers competing represents a competitive market structure. A structure where no sellers exist is not reflective of any market operation, and a situation of shared market control among buyers does not correspond with how monopolies function, as it suggests a breakdown of typical seller control rather than singular dominance.