Imperfect competition refers to a market structure where no single firm has complete control over the market, leading to a variety of products and pricing strategies. Unlike perfect competition, where many firms sell identical products, imperfect competition includes scenarios like monopolistic competition and oligopoly, where firms can differentiate their products and influence prices. In imperfectly competitive markets, companies often engage in advertising and branding to attract customers, which can lead to higher prices than in perfectly competitive markets. This structure allows for some degree of market power, enabling firms to set prices above marginal costs, resulting in potential inefficiencies in resource allocation.