KiCad creates a file, extension .net, for holding certain basic, defining information about the project.
The net list holds much more that just a list of the "nets", at least more than just a list of the nets, if you use that term in a very narrow sense.
The net list is one of the major mechanisms coordinating the operation of the various elements of KiCad.
You've been working on a schematic.
You want to move on to the PCB design. Or you are in the midst of the loop of "tweak schematic/ tweak PCB".
If you have done the basic introductory exercise, you will be familiar with the CvPCB tool, for "matching up" the schematic symbols of the devices on your schematic with footprints for them on the PCB.
Be sure to "generate netlist" AFTER you have run CvPCB. (The netlist is also the repository of the information prepared by CvPCB.)
The file is "the net list" in one sense, but while working with KiCad, you will frequently be thinking about the information in the file, as a more abstract meaning of the term. The two uses should not, I hope, clash and confuse you.
(This entry needs expanding! If you particularly want THIS expanded, write and cite "Page co1netlist")