Ask HN: Can I use a name from a novel for my company?

I'm a fan of George R R Martin's A Song of Ice and Fire and among many things, I like his creativity with names. I was wondering if I can use a name from his series for my company. Perhaps I should ask this question directly from him, but he seems unapproachable.

So the question is, is it fine if I use a name from his books for my company without informing him in advance? Is there any legal problem with it? Is there any moral problem with it? If yes, how would you avoid them? Have you ever borrowed name of your company from a book?

Any hints/clues/ideas will be appreciated.