1. Foreign exchange refers to foreign currencies and bank deposits denominated in foreign currencies that are traded on foreign exchange markets globally.
2. Exchange rates represent the price at which one country's currency can be traded for another's. Nominal exchange rates are the relative prices of currencies, while real exchange rates also account for differences in inflation between countries.
3. The Big Mac Index published by The Economist uses the global price of McDonald's Big Macs to estimate purchasing power parity exchange rates between currencies based on the theory that the same good should cost the same in different countries when prices are adjusted for exchange rates.