Definition of atheists:
(n) :
(religion) A person who does not believe in deities or gods.
(n) :
(strictly) A person who is certain that no deities exist or who thinks that the existence of deities can be disproven.
(n) :
(loosely) A person who doubts the existence of deities (therefore, an agnostic may be considered an atheist).
(n) :
(very broadly) Any person lacking belief in deities (including children who are unaware of religion).
(n) :
(sometimes proscribed) A person who does not believe in any religion (not even a religion without gods); a nonreligious person.
(n) :
(uncommon) A person who does not believe in a particular deity (but may believe in another deity).