Hello
I think a simple misunderstanding of what was meant by "BASE ITEM".
~Base item~ this is an object in the game that can be created, it also serves as a base for the; type, material, weight, purpose etc.
So for your code;
.Fiber Cord. "Cord" etc etc
would be the proper usage.
This will create an item called "Fiber Cord" the item will be Cord behind the scenes unless you change other properties.
Have fun
Oh btw for a good list of all the items (well the vast majority) the file "create_objects.txt" has it for whatever version you are running.