Class

One fund can offer multiple classes of shares, often referred to as Class A shares, Class B shares, and so on. Each class has different fees and expenses for the same fund. Look in the prospectus to see if a particular fund offers more than one class.

The class that is best for you will depend on various factors, such as how much you plan to invest and how many years you plan to hold your investment. Remember, not all funds have classes, so don't be alarmed if the prospectus doesn't mention them. However, if a particular fund offers more than one class, you will need to make sure you use the information from the correct class.

http://www.sec.gov/investor/tools/mfcc/classes-help.htm