Commerce Server
An application program that runs on a server tier computer. A typical commerce server obtains product data from a database, manages items in users' shopping carts, and coordinates the checkout process.
A .xlsx file tells you that the file is an Excel workbook that utilizes XML files to create the various spreadsheets as well as macros and other hidden codes used to perform certain functions (which is why there's an X at the end; older .xls files had no indication of this external code being present, which is why they're almost never recommended for modern use).
