A monopoly occurs when a single company or entity dominates a market, controlling the supply of a product or service. This lack of competition can lead to higher prices and reduced choices for consumers, as the monopolist can set prices without concern for rivals. Governments often regulate monopolies to prevent abuse of power and protect consumer interests. In some cases, they may break up monopolies or impose rules to encourage competition. Examples of monopolistic practices can be seen in industries like utilities or technology, where a few companies may hold significant market share.