The term economies of agglomeration is used in urban economics to describe the benefits that firms obtain when locating near each other. This concept relates to the idea of economies of scale and network effects. Simply put, as more firms in related industries cluster together, costs of production may decline significantly. Even when multiple firms in the same sector cluster, there may be advantages because that cluster attracts more suppliers and customers than a single firm could alone. Cities form and grow to exploit economies of agglomeration.