I always wondered how to correctly abbreviate dollars, and it turns out there are several ways. The symbol $ is the most common you see everywhere, but there's also USD, which is the official international abbreviation according to ISO 4217. So when you see abbreviated dollars, it can be in either way.

The interesting thing is that the dollar is not just the currency of the United States, but it practically dominates the world. It is the most important reserve currency internationally and is used in most global transactions. Entire countries have directly adopted the dollar as their official currency, and others simply peg their local currency's exchange rate to the dollar. Pretty crazy when you think about it.

The monetary policy behind all this is managed by the Federal Reserve, which is basically the central bank of the United States. They control the issuance of dollars and everything involved. That’s why when there are changes in the Fed’s decisions, the global market moves. The dollar really is the king of currencies, regardless of how it’s abbreviated.