In the process of revising - which is taking longer the more I procrastinate - I came across something shocking. After laboring over a name for my faerie world, after thinking up cool words that meant something interesting, after finally deciding and falling in love with the word I chose... I discovered someone else had already used it. They didn't use it as the name for a world, though. It's the name of a character (a main character) and the title of The Books of Umber series by P.W. Catanese. Umber. Who would've thought? I know about the City of Ember and the other books in that series, but somehow this had passed under my radar! I feel terribly ignorant and foolish for not doing my homework this time.
The worst part is, these books are recent! The first was published in 2009 and somehow I missed it! I emailed my agent to ask if I'll be in trouble using it as the name of my world as long as I don't use it in the title of the books. I'm hoping the answer is yes. I really am attached to the name and what it conveys for me - the atmosphere of the place, the mystery, the shadowy abyssal quality I want to lurk in readers' minds.
This is a rotten predicament, and I know other authors have had the same thing happen to them. I was trying very hard not to fall into this situation, but it looks like it happened anyway.
Advice I'd have for anyone who is worried about the same thing - google everything you think you might want to use, check on associations and connections (because readers will draw them, whether you like it or not) between your book and others with the same names. You'll be glad you did.