This one is yet again at the request of my kids, who asked why in the world we abbreviate “dollar” with $. (They also asked why they sometimes have one line through it and other times two.)
So…though it has been suggested by some historians that the $ is related to the 8, for the Spanish pieces of eight that were frequently used as currency in Ye Olde Days, the more accepted history is that it’s in fact from the peso, which we also used before the Revolution. Peso was abbreviated with a capital P and then a superscript S. In handwriting, people began to write the two letters overtop each other. And so it evolved as in the diagram below.
By why do some dollar signs have two lines? The theory is that it used to be to differentiate the US dollar. Given that $ was already in use by then, the two lines are thought to have once formed a U. Also in the diagram below.
These began to appear in handwriting in the 1770s and in print in the early 1800s.
|Image by JesperZedlitz|
So where did the word dollar itself come from? It’s from Flemish daler, which is short for Joachmistaler, which was a coin mined from the silver in Joachimstal, Bohemia. Daler was borrowed as a term for coins used in both Spanish and British colonies in the Americas during the Revolution and became the official US currency in the late 1700s.
That's pretty interesting!