religion
[ ri-lij-uhn ]
noun
1. a set of beliefs concerning the cause, nature, and purpose of the universe, especially when considered as the creation of a superhuman agency or agencies, usually involving devotional and ritual observances, and often containing a moral code governing the conduct of human affairs.
2. a specific fundamental set of beliefs and practices generally agreed upon by a number of persons or sects: the Christian religion; the Buddhist religion.
3. the body of persons adhering to a particular set of beliefs and practices: a world council of religions.
4. the life or state of a monk, nun, etc.: to enter religion.
5. the practice of religious beliefs; ritual observance of faith.
6. something one believes in and follows devotedly; a point or matter of ethics or conscience: to make a religion of fighting prejudice.
Note the definition in #6. If you believe in and follow devotedly, the point or matter of ethics or conscience which suggests that religion doesn't exist, you simply have a religion of non-religion.
If you believe in and follow devotedly, the point or matter of ethics or conscience which suggests that atheism is not a religion, you simply have the religion of saying that atheism is not a religion.
If you believe in and follow devotedly, the point or matter of ethics or conscience called atheism, you simply have a religion of atheism.