A reserve currency is a foreign currency that is held in significant quantities by central banks or other monetary authorities as part of their foreign exchange reserves. The reserve currency can be used in international transactions, international investments and all aspects of the global economy. It is often considered a hard currency or safe-haven currency.

Sterling is the currency of the United Kingdom and nine of its associated territories. The pound is the main unit of sterling, and the word pound is also used to refer to the British currency generally, often qualified in international contexts as the British pound or the pound sterling.