From Verinfall Archives

The Great Exile refers to the act of Hector I banishing all magic from Altera. Magic has been nonexistent for thousands of years (3017 years) but following the events of the 17th of September, the world will now never be the same.

In relation to the event, Exile refers to the act of the banishing of magic.

In relation to time, Exile, or Post Exile (PE) refers to the time since the banishment of magic on a yearly system.