AUD/USD is the Forex pair that represents the Australian Dollar versus the US dollar. The pair is notable for its trending potential given divergence between Australian and US economies. The carry trade was a popular strategy here in the post-Financial Collapse backdrop, when the Australian economy had weathered the storm better than the US. This allowed for the Reserve Bank of Australia (RBA) to keep interest rates relatively high while US rates were pegged to the lower bound.
Australia is noted for its significant deposits of natural resources, particularly metals, and for many years the currency was though to track Gold prices given the significant Gold deposits that can be found in the country.