Fair usage; I advised JimRob on this issue early in FR history.
***If they are invented words....then did they trademark/copyright the word? If not I don't see why you can't use it.***
The simple answer is 'yes' it can be copyrighted - intellectual property. You are addressing some fairly complicated international legal issues... which I am in no position to pursue, especially now. But they have been tested in court re: Tolkien.
Mark