Reading through the last few pages has taught me that some people still don't know how to google a word they don't know.
Atheism, as has been reiterated, is a lack of belief in God(s).
It is a lack of Theism. Theism is the belief in some form of God(s).
'a' means to be without (as another member has said).
'a'theism means to be without theism.
Theism is a belief in God(s).
Atheism therefore means to be without a belief in God(s).
It's not that difficult.
Now on the issue of "God(s)".
Gods have not been proven to be objectively real.
When someone says that a God or many Gods exist, they are making a
claim.
The Burden of Proof (BOP) resides with the party making a claim without evidence.
By default, the BOP rests with theists of all forms, as they are making an unsupportable claim.
They are doing so simply by being a theist, by having a God belief.