microsoft excel

Terminology!

Excel is the application.
What you build with Excel is the Application Project.
A sheet is a Work Area, hence WorkSheet.
A macro is a recorded set of key-strokes.
A function is a built-in tool for working with information in a cell(s) of a worksheet.
When you have more than one worksheet, with one or more of the sheets referring to information on other sheets. Then, you have a 3D application project. If your application project has one or more sheets and can stand alone as an application project, then it is a Workbook.
A User Form is an over-lay of a worksheet that acts as a Frame on which actions not directly involving cells on the worksheet, can interact with information that may or may not affect worksheet cells.
VB is Visual Basic, a programming language which can extend the operation of Excel beyond the standard package ability.
VBA is Visual Basic for Applications. In Excel VBA has extensions to VB to work with the unique aspects of Excel. Macro like blocks of code are written by the user, to build custom abilities into Excel.

There is more, but these are the bigges. All or some of the above is used to record, manipulate and analyze data. The project can include a simple spreadsheet, used to list data and do mathematical processes with it. Or, a project could include multiple worksheets, organizing different types of data, provide statistical information about the data. Then, output that information in a report form for viewing and printing. The more advanced workbooks can link to other workbooks, import and export data to other applications, publish to the web and incorporate custom user interfaces to tie it all together