Thanks, akhtene!
This is very off topic, but still interesting. I think you're not far off making the comparison between Numenor and Atlantis. One of the names for Numenor after it's downfall was
Atalante, a choice of name that brings to mind Avallone's similarities to Avalon.
And on another note, C.S. Lewis in
That Hideous Strength makes reference to "Numenore" in connection with Merlin (who is also associated with Atlantis in some contexts). Since they were working simultaneously on space/time travel stories, I don't find it hard to believe that Tolkien knew Lewis planned to make this reference.
Apologies for the straying from topic [img]smilies/rolleyes.gif[/img] . As for Eucatastrophe, it isn't surprising that your dictionaries didn't list it, as it's a term Tolkien coined for a certain emotional response to unexpected hope in an overwhelmingly dark situation (or at least that's my rather ungifted paraphrase). Here's a thread that will tell you
more about eucatastrophe than you could ever need to know.
Sophia