As others have said, Atheists don't believe in any gods. Most Atheists would argue that Atheism is not a religion, because it is an unorganised belief system (in the sense that there are no specific doctrines, no designated leaders and too wide a variety of beliefs etc).
To further illustrate, check out this pick from the Agnosticism spot:
link There are certain "levels" of Atheism/Agnosticism that 更多 accurately describe individual's beliefs. I suggest also checking out the Agnosticism spot:
link Agnosticism is a varied belief system as well, but it focuses on the belief that people do not know and/or cannot know the true nature of the universe/the existence of gods etc.
Feel free to visit the Atheist club on Fanpop:
link 你 can take a look around, but be warned that there are anti-religion sentiments there. 你 will probably also see a number of instances where religious people have come to the club and attack our beliefs. A lot of those conversations are quite offensive to all parties. But 你 will also find some great conversations between religios people and Atheists, as well as conversations between Atheists that 显示 that Atheism isn't as simple a belief system as the dictionary definitions imply. If 你 have any questions, I suggest that 你 check out this forum:
link 你 may find some 答案 there, and if not, 你 can ask us! There are lots of great 论坛 there for anyone to check out. All that we ask is that 你 treat us with respect. Treat us in the same way 你 would want to be treated.
I don't mean to sound like I'm advertising 或者 anything. I just think that this is a great question, and it is great that 你 didn't just accept those simple definitions of Atheism that 你 found.