Formally speaking, foreign exchange is a foreign currency or foreign currency assets, but it cannot be considered that all non-domestic currencies are foreign exchange, and only those convertible foreign currencies can become foreign exchange.

Foreign currency is a static concept, which refers to the means of payment expressed in foreign currency and can be used for international settlement.

Foreign exchange is a dynamic concept, which includes credit instruments and securities expressed in foreign currency.

Different concepts: foreign currency refers to the currency of other countries or regions other than the domestic currency.

Foreign exchange refers to foreign currency or various means of payment expressed in foreign currency used for international creditor's rights and debts settlement.

Different functions: foreign currency is often used for foreign settlement business caused by economic activities such as trade and investment. Foreign currency refers to another currency used in the official currency area or a payment request made in another currency.

Foreign exchange refers to a specialized business activity of converting one country's currency into another country's currency to pay off international creditor's rights and debts.