| Currencies are country specific way to name money. In the US we use the dollar. In Europe they use the Euro and in Japan they use the Yen. You can see a list of currencies.
Some countries use the term dollar but a US dollar and a Canadian dollar don't mean the same thing. To identify a currency there is a standard 3 character currency code that represents the currency. The first two characters are usually a country identifier and the 3rd character is the currency name. For example USD, US is the country and D is for Dollar. A currencies value can vary over time, going up or down usually based on a number of factors but mostly supply and demand. |