In Excel what is a list?

It is like the ordinary understanding of a list, in that it is a set of values that are listed in your spreadsheet. You can set up special Custom Lists and do things like sort them or get calculations from them or get them to automatically generate themselves when you type in one value and then drag down. There are a number of in-built custom lists in Excel. If you type in any day of the week or any month of they year into a cell, and then click and drag on the fill handle, it will fill out subsequent days or months. You will find Custom Lists under the Tools menu under Options.