market structure

The interconnected characteristics of a market, such as the number and relative strength of buyers and sellers and degree of collusion among them, level and forms of competition, extent of product differentiation, and ease of entry into and exit from the market

Four basic types of market structure are (1) Perfect competition: many buyers and sellers, none being able to influence prices. (2) Oligopoly: several large sellers who have some control over the prices. (3) Monopoly: single seller with considerable control over supply and prices. (4) Monopsony: single buyer with considerable control over demand and prices.