I was torn on what to call it - debated using the term "state failure", which I think is more accurate but few people truly know what that means. Basically, I'm referring to an event that breaks our conceptions of what it means to be "civilized" - basically, that you follow laws, adhere to contracts, respect government authority, have a well-defined political process, pay with a stable currency, can count on your personal property rights and past savings being respected, etc.

You can have civilization-ending events that don't involve everyone dying - the fall of the Soviet Union in 1991 was one. It was still hugely disruptive to everyone who lived in the Eastern Bloc. The U.S. Civil War is another one, though plenty of people died then too. It's not the end of all civilization, just the civilization we're in.