Many currencies have slang (informal ) names. For example the currency in England and Great Britain is called the pound (or pound sterling) but people call it a quid in slang. The dollar is used in the USA but people also refer to it as a buck. These are slang names not the official name of the currencies.I have never heard of a loonie.A pound is 100 pence and a dollar is 100 cents.

In Australia, we mostly just say 'dollars'. 'bucks' is used as slang sometimes, but probably not as much as it used to be. Other slang terms include: A fiver - A five dollar note. Ten grand - 10,000 dollars. Shrapnel - small loose change that one wants to unload.

In Canada: 1 dollar = 100 cents Informally, the dollar is also called a "buck" or a "loonie". The word loonie comes from the fact that the one dollar coin has a picture of a loon (a kind of water bird) on it. Smaller coins are: half-dollar = 50 cents (most people don't carry these in their pocket) quarter = 25 cents dime = 10 cents nickel = 5 cents penny = 1 cent However, Canada did away with the penny in 2013 so you don't see pennies in circulation anymore.

Each country has official names for currencies. Then there are popular or favorite or pet names for money. I think that most currencies work on the decimal system now. 100 cents or 100 pennies = 1 dollar US. 100 euro cents = 1 euro etc