Way back in 1653, when New York was New Amsterdam, the first line of defense for the colony was a simple earthwork redoubt that was designed to keep people out. Over time the redoubt was replaced with a wooden stockade. The road that followed along the inside of the stockade became known as Wall Street.
Even in the early days merchants and traders would set up along Wall Street to sell stocks and bonds and trade securities. Eventually, this street became the financial center of the city and colony. In 1792 a group of these men got together and created the basis for what would become the New York Stock Exchange.
In a completely unrelated note (cough, cough), when the US Constitution was ratified New York became the capital of the new country for the first couple of years. The old City Hall was refurbished into Federal Hall where the new Senate and House of Representatives would meet. This building sat smack in the middle of Wall Street. Setting no precedents what so ever…