The Lesser Rings

[Boromir88]

Originally Posted by jallanite

It is clear to me also that Gandalf is supposed to know the meaning of the word. What is not clear is which possible meaning Gandalf intends when both suggested meanings may work.

I don't know, this is something that is pretty clear to be both meanings. The blades being imbued with "black sorcery" but also being crafted in/around Minas Morgul. In The Siege of Gondor and Pelennor chapters, when necessary there are clear distinctions between the Morgul-host (ergo the host from Minas Morgul) and the other individual parts comprising the entire army (under the command of the Witch-King):

...from under the walls came the legions of Morgul and from the southward fields came footmen from Harad with horsemen behind them. ~The Battle of Pelennor Fields

"the legions of Morgul" meaning the host out of Minas Morgul, and to describe the movements of another individual part of the whole host, "footmen from Harad"

And towards the end of the same chapter:

Few ever came eastward to Morgul or Mordor...

Basically, "Morgul" is often used, and acceptable shorthand for "Minas Morgul" or in general the area surrounding Minas Morgul...Imlad Morgul, the Morgulduin..etc. And therefor, the Morgul-knives would, to me, mean the knives were made in Morgul, and they just happen to have a fitting double-meaning being blades enchanted with black sorcery.