Religion comes from Re- (Re) -ligion (union), which usually ends up meaning [i]Reunion of people[/i]. There can be religion without God, an Atheists belong to a religion that [b]doesn't[/b] believe in God, period. People who justify their actions upon "God's will" are wrong. Theism is a lie too, as religion is supposed to be based on mutual support to achieve spiritual freedom, not fanatical worship over a God, used to manipulate weaker minds into their cause. Now, deism is a different thing, it [i]is[/i] the way religion was always intended to be, an interpretation to live life based on teachings, that help humanity to achieve plenitude. So in the end, theism is just a way to justify inhuman actions (looking at you extreme muslims), atheism [b]is a religion[/b], and deism is the way to live religion as a reunion of people with the same beliefs.