What is a base currency?
A base currency is the first currency that appears in a forex pair quotation. In the foreign exchange market, one currency will always be quoted in relation to another because you are buying one while selling the other.
The base currency will appear first, and will be followed by the second currency, known as the quote or counter currency. The price displayed on a chart will always be the quote currency - it represents the amount of the quote currency you will need to spend in order to purchase one unit of the base currency.