Investment return is the reward, or loss, that one receives for partaking in an investment. Returns are usually something you need to look at as potential, because one can never really know how an investment will perform. Most people will buy an investment to make money from it, but sometimes, for the few people who are disgustingly rich enough and have made too much money, they will try to invest to make a loss, to have a tax write-off on their taxes. An investment's return can vary from day to day and year to year. Sometimes an investment can have a spectacular year and the next year, be in the dumps. Returns are normally reliant on what the market for that particular investment dictates. One way to get an idea of what kind of returns an investment can offer, one could look at the historical figures* and also, and this is important, the risks involved. i.e. a low risk investment, such as a money market, will offer a lot less potential return than an investment in a stock, but your chance of loss with the money market is practically nil.
*A word about historical returns: Historical returns do not guarantee future results.