A market structure characterized by a large number of small firms, similar but not identical products sold by all firms, relative freedom of entry into and exit out of the industry, and extensive knowledge of prices and technology. This is one of four basic market structures. The other three are perfect competition, monopoly, and oligopoly. Monopolistic competition approximates most of the characteristics of perfect competition, but falls short of reaching the ideal benchmark that IS perfect competition. It is the best approximation of perfect competition that the real world offers.