An archverse is a high-level -verse of unknown size and origin. In Second_Soup's twin cosmologies, they fill every gap between the Omniverse and megaverses in scale; the infinite stack of structures past a megaverse can be called archverses. In Holomanga's level system, they are of an extremely high level; some might have a level of a million, a billion, or much more.
At this scale, humans are unable to describe what exactly an archverse resembles. Conceivably, the higher-level archverses contain every permutation of every universe, multiverse, and megaverse, meaning that there are an infinite number of exact copies of every single world, down to quantum precision, somewhere in the local archverse cluster!