Its the relative path which you are using to point to your document.
Let me give you an example how it works.
Say for example you have all your working files at
D:\QlikView\Working folder, Qvds at D:\QlikView\Qvds.
Now if you want to add qvd to your application residing in folder working, you can do following way.
1. Absolute path i.e
Load * from d:\QlikView\Qvds\Abc.Qvd(Qvd);
2. Relative path
Load * from ..\Qvds\Abc.Qvd(Qvd);
Here in relative path you are saying. Pick my current application path and (..) means go one directory out (Meaning go Back to QlikView folder) then go to Qvds and get the Abc.qvd.
So the number of times (..) will depend on how deep you are into the folder structure.
Hope this will help.