The Monoverse is the theory that explains that there is an infinite amount of universes within an infinite amount of space occupying is a universe that contains all the universes, called, simply, the monoverse. Yet, they all occupy the same enclosed space.
The Monoverse contains all of existence, and anything outside of the monoverse does not exist in the sense of actually existing. The area outside of the Monoverse is called the All-Encompassing Outer Non-Existence, and encompasses all the different universal dimensions.
The actual layout of the Monoverse is shown by having a “Core Universe” that is surrounded by different layers of “Bubble Universes” covering the outside of the Core Universe. The Core Universe is considered the “original universe” with the bubble universes being the copies/reiterations of the Core Universe.
The Monoverse is different from a "polyverse" or "metaverse." The word itself is less about describing whether there are multiple universes or even a single universe, but everything as a whole. The “One Existence” would be a more applicable definition for the word “Monoverse” — there is “one” universe, and the universe the Monoverse describes is absolutely everything, without the question of whether there is something bigger, because there isn't.