Terms of trade refer to the ratio between the price of a country's exports and the price of its imports. It measures how much of a country's imports can be exchanged for a unit of its exports. For example, if a country exports crude oil for $100 per barrel and imports wheat for $200 per ton, the terms of trade would be 0.5 barrels of oil per ton of wheat. Generally, a higher ratio indicates that a country can purchase more imports for a given amount of exports, which is considered favorable for its economy.