What is referred to as the ability of a single economic actor to significantly influence market prices?

Market power refers to the ability of a single economic actor, such as a firm or a seller, to influence the price of a product or service in the marketplace. This influence can stem from various factors, including the actor's size, market share, lack of competition, or unique product offerings. When an entity has market power, it can set prices above the competitive equilibrium level, leading to higher profits and affecting consumer choices and overall market dynamics.

In contrast, the other concepts do not pertain directly to the influence over market prices. Redistributing income involves altering how income is spread across different groups in society and does not inherently change market prices. Externalities relate to the side effects or consequences of an economic activity that affect other parties who did not choose to be involved in that activity, rather than the direct control over prices. The standard of living is a measure of the wealth, comfort, and access to essentials that individuals or communities possess, which is influenced by many factors beyond just the pricing power of a single actor.