The concept of mercantilism is most closely associated with triangular trade. This economic theory, prominent from the 16th to the 18th centuries, focused on increasing a nation's wealth through a favorable balance of trade, particularly by accumulating precious metals and controlling colonial trade.
Triangular trade refers to the transatlantic system of trade in the 17th and 18th centuries where goods and enslaved people were exchanged between Europe, Africa, and the Americas. European nations would export manufactured goods to Africa, trade them for enslaved individuals, transport those individuals to the Americas, and then return with raw materials (such as sugar, tobacco, and cotton) to Europe. This cycle of trade exemplifies the mercantilist idea of maximizing profit through controlled trade relationships.
Quadrilateral trade and octagonal trade are not recognized concepts in economic history related to mercantilism.