In the Dragonlance books, the Cataclysm was a catastrophic event that occurred when the Kingpriest of Istar demanded that Paladine, the god of good, eliminate evil from the world. The gods responded by dropping a mountain on Istar and inflicting various other large-scale disasters on the world to punish mortals for their arrogance.

Post-Cataclysm time in Krynn is often rendered AC, to denote "After Cataclysm.