Which term describes a market characterized by a single seller with high barriers to entry for other firms?

The term that accurately describes a market characterized by a single seller with high barriers to entry for other firms is “monopoly.” In a monopoly, one company dominates the entire market, allowing it to control prices, supply, and overall market conditions without competition. The presence of high barriers to entry, such as significant costs, legal restrictions, or unique technology, prevents other potential competitors from entering the market and challenging the monopolist's position.

This control and limitation of competition is what defines a monopoly, distinguishing it from other market structures such as monopolistic competition, where many firms can enter the market and competition exists, or oligopoly, where a few firms dominate but competition is still present among them. Pure competition also allows for many sellers and minimal barriers to entry, which is the opposite of what defines a monopoly. Thus, the defining characteristics of a monopoly make it the correct term to describe the market scenario in question.