This is an ever growing stock market dictionary (investment dictionary) for information on the terms of investing and the stock and bond market and many other Wall Street definitions. We are always being asked, what is a preferred stock and why is it different from a common stock? What are pink sheet stocks and why do they call them pink sheets? Are there yellow sheets, blue sheets, or any other color? Concise definitions are provided through the following links, everything from accrued interest to zero coupon bonds. We continue to add to the list on a regular basis, as the list of investment words continue to grow.