Religion (n.) - The Church Is The State
Devotion to or veneration of a particular set of morals or moral authority, usually of divine origin.
History & Etymology
The most distant origins of the word religion are disputed, to say the least. There seem to be three popular theories.
Cicero had the idea that it came from Latin words meaning to “go through again,” with the prefix re- meaning again and legere meaning to read.
Later thinkers such as Servius, Lactantius, Augustine preferred an origin of the word coming from religare "to bind fast" related to words like rely. The idea is that it referred to the bond between men and the gods, or to be bound by an oath.
Another possible etymology is related to the word religiens which in latin is the opposite of negligens. It meant careful.
The English definition we’re used to wasn’t used until the 1300s, and the even more specific meaning relating to higher powers and gods wasn’t common until 1530.
My best guess as to which possibility is correct leans towards the second one where it means “to bind or to become bound to.”
In the ancient world religion and politics were the same thing. They were both about what you bound yourself to. If you lived in a city you were bound to the gods of that city or the nation or the empire. In many cases, you were bound to the leader as if he were a god.