"I am an atheist, but I know better than to claim that there is no God"
Then you are not an atheist.
The definition of atheism is that you affirmatively believe in the absence of any God--regardless of definition.
No, the definition of atheism is the abscence of theism. A = without, theism = belief in a god or gods. Atheism = without belief in a god or gods. I do not believe in any deities, therefore I am an atheist.