The Sects of Atheism

[Angrboda]

The correct answer for the dictionary definition of an atheist is : “I don’t know” regarding the existence of the afterlife and souls. A few of you have said that, in different words. 

You seem to be under the impression that views on gods necessarily entails specific views on souls and the afterlife. They do not. I can be an atheist and believe in the existence of souls and an afterlife. Some belief systems about gods assume things about gods, souls, and the afterlife. Belief in the Christian god entails beliefs about souls and the afterlife, but atheism isn't about the Christian god alone. Atheism in general isn't one of those belief systems and says nothing about souls and the afterlife.

By the way, dictionaries disagree on proper usage, but in general only report how people use a word; they really have no authority to dictate how a word should be used.