The view that there are no gods. A widely used sense denotes merely not believing in God and is consistent with agnosticism. A stricter sense denotes a belief that there is no God; this use has become the standard one. In the Apology Socrates is accused of atheism for not believing in the official Athenian gods. Some distinguish between theoretical atheism and practical atheism. A theoretical atheist is one who self-consciously denies the existence of a supreme being, whereas a practical atheist may believe that a supreme being exists but lives as though there were no god. L.P.P.
Summary Article: atheism from The Cambridge Dictionary of Philosophy