The U.S. dollar is the currency most used in international transactions. Several countries use the U.S. dollar as their official currency, and many others allow it to be used in a de facto capacity. It's known locally as a buck or greenback.
The Australian Dollar is currently the fifth-most-traded currency in world foreign exchange markets. It is also used in the Christmas Island, Cocos (Keeling) Islands, and Norfolk Island, as well as the independent Pacific Island states of Kiribati, Nauru and Tuvalu.
