Cosmic Void

A Cosmic Void is a subset of an Universe, which doesn't contain a lot of galaxy clusters, although it contains 0.01% of galaxies
They're the set of all space of a Universe, which doesn't contain any matter. It is therefore intuitive, that the union of the Cosmic Voids and all matter are the Universes themselves. In the case of our Universe, this "matter" would be the Cosmic Web, or Supercluster Complexes. 
Sometimes, specific Cosmic Voids are labeled by name, mostly due to their proportions, but sometimes also for their contents, or lack thereof. 
Category:Void
Category:1st-class
Category:Class 0
Category:Navigable
Category:Non-verse