The trade balance or the export-import balance is the difference between the value of a country's exports and imports in a given period, measured using the prevailing currency. A positive balance means a trade surplus if the export value is higher than import, and vice versa for the negative balance. The trade balance is often divided on the basis of goods and services sectors.
Economic policies in various countries in Europe in the Middle Ages were grouped into mercantilism. Initial understanding of trade imbalances arose from the practice and misappropriation of mercantilism when the resources of the colonies in the Americas were exported in exchange for finished goods from Britain, which then sparked the American Revolution