"Even if a grant you that ‘a’ means ‘without’ we have not come to the conclusion that Atheism means ‘without belief in God’. What is negated in the word is ‘God’ not ‘belief’. In the etymology of the word there is no concept of belief. We can go as to meaning ‘a universe without God’ which is another way of saying ‘God does not exist’ , affirming the non existence of God"
No, it's pretty simple. Without god. Not having god. That's all atheism is. You are apparently trying to turn it into a belief that there is no god. A believer will say "I believe there is an invisible table in the middle of that room." A nonbeliever will simply say it's an empty room. They would not say "I absolutely do not believe there is a table in this room".