just a quickie here....the origin of the word "dollar" is even more interesting. and the history too. right before the introduction of the U.S. dollar, the popular form of exchange was the spanish piece of eight. it was a single coin one eighth the value of a real. there is actually a history of american bank notes as they exist today and the first use of it predated the revolutionary war. all quite fascinating stuff.
i strongly suggest you read "the creature from jeckyl island" by g. edward griffin if you want to know how the system works and more about it's history.