Just a word, just a word, old chap. Words are wot people mean them to be, otherwise language collapses. "Atheist" is no more than a term of convenience, as it's such a hard concept for people of belief to get their heads round. And a lot depends on whoever it was who invented the word. I hate to be characterised by a single word, but, in modern parlance, I'm an atheist and there's no getting away from it. Once again, the "a" in atheist puts me in the negative, which I'm not having. "Atheist" wouldn't even be a word at all were it not for the highly-irrational billions who "believe in God." It's a word necessitated by their delusion. Think about that.