International reserves are any kind of reserve funds that pass between the central banks of different countries in the world as an acceptable form of payment. The reserves can either be gold or some else specific currency, like dollar or euro.
Another term for foreign currency reserves is foreign-exchange reserves or forex reserves. They can also be used to pay its liabilities if necessary, and they are held either in one or more reserve currencies. In order to find out which country has the most check out Top 25 Countries with Highest Foreign Currency Reserves in the World!