AUD/USD
The abbreviation for the Australian dollar and U.S. dollar (AUD/USD) currency pair or cross. It is also referred to as the Aussie among forex traders.
In the AUD/USD, the base currency is the AUD and the quote currency is the USD. In other words we are referring to how much USD is required to buy one unit of AUD.
Let us have an easy example for clarification purposes. If the exchange rate of 1 AUD is 2 USD, then you need to pay 100 USD to purchase 50 AUD.