I might be wrong, but I thought atheism was when you didn't believe in God or a higher being (such as Budah, Mohamad, or other "higher beings" that other religions believe in. They more believe in the big bang or evolution theory. But I am definetly not the expert, someone else might know for sure more about it, that is just what I always thought. Just not going to church and ignoring Christianity isn't necessarily atheism.