In foreign exchange trading, the “Base” currency is the first currency in the pair (the fixed amount). The “Quote” currency is the second currency in the pair. This is the value that changes and determines profits and losses.
For example, if you purchase a JPY/USD pair that is quoted at 1.30, then for every 1.3 USD you sell you get 1 JPY. The base currency is the Japanese yen, the quote currency is the US dollar.