A stock index or stock market index is a method of measuring the value of a section of the stock market. It is computed from the prices of selected stocks (typically a weighted average).
An equity investment generally refers to the buying and holding of shares of stock on a stock market by individuals and firms in anticipation of Income from dividends and capital gains, as the value of the stock rises.
Unfortunately risk is not understood by many investors. In short run, risk is in volatility of price of underlying asset i.e., how much it can rise and fall given a period of time. But in long run risk is not volatility but the risk is to maintain the purchasing power of your money.
Financial centers around the world function as anchors of trading between a wide range of different types of buyers and sellers around the clock, with the exception of weekends. As a forex trader you can choose a currency pair that you expect to change in value and place a trade accordingly.