Regardless of its etymology, the word atheism as it's currently used - and remember, dictionaries record usage of language, they don't define it - means "not theism". That's the definition I go with, as to me it's the most accurate summation of my position. A theist believes in gods, I am not a theist, I do not have a theist position. I am thus a-theist.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'