lol @ picking out a random google definition that is outdated to what Atheism actually means (linguistically). I can do that too.
Atheism is, in a broad sense, the rejection of belief in the existence of deities.
a lack of belief in the existence of God or gods
One who rejects theism.
Basic atheism is not a belief. It is the lack of belief. There is a difference between believing there is no god and not believing there is a god--both are atheistic, though popular usage has ignored the latter.
Also, the 'a' in atheist derives from the greek for 'without'. Atheism is 'without belief'. It is NOT a belief system, it is the rejection of one on logical and rational grounds.
It's really not a difficult concept and it shouldn't have taken you 3 pages and counting to understand it.