1. In general, the functionality of something refers to the overall quality and how well something performs. For example, a software program may have improved functionality over previous versions with new features and options that were not available in past versions.
3. Excel functions are built in to help provide one word access to a series of operations. There are several dozen different functions, and they are organized according to their purposes. For example, in the excel formula =SUM(A1:A10) SUM is the function of the formula that adds all the numbers in the range of cells. You can go to Formulas tab (in Excel 2010) or click the formulas button and see all available functions as shown in the example below.