A hubworld is a type of universe that is particularly well-connected to the other universes within its multiverse. Portals and space bridges between different universes and the hubworld often form, letting objects or even sentient beings pass through.

Highly-advanced civilizations and developing entities beginning to explore their multiverse are likely to encounter hubworlds before most others, meaning that such early pioneers have a potential strategic asset or meeting point at their disposal. Since shutting down a hubworld's inbound connections is often infeasible, using them for storage or defense is difficult; it is all too easy for snoops of various sorts to stumble into even heavily guarded hubworlds. Paranoid or destructive beings can use physics manipulation or more conventional methods to configure hubworlds into traps, innocuous when merely observed but lethal to any attempting to enter. On the other end of the spectrum, some civilizations find them natural points for colonization and cooperation with extrauniversal life. An inhabited hubworld can fit Dyson spheres, Megarings, or other megastructures of galactic or supragalactic size, either constructed in patchwork by the network of civilizations and entities that arrive or built in preparation by the first explorers. Such inhabited hubworlds generally rely on an extensive defense network, as there is no guarantee that new arrivals will be friendly.

The concept of a hubworld is not unique to the universal scale; larger -verses can easily serve as connection points for even larger civilizations, entities, and phenomena. One possible nomenclature for these is to call a multiverse-scale hubworld a multihub, a megaverse-scale one a megahub, and so on up the archverse chain.

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