A pocket universe is a tiny self-contained universe that can be accessed through normal universes via portals or other transfer mechanisms.[1]


A Pocket universe obviously vary in size, though one definition is that a pocket universe has a maximum diameter beyond which it is classified a universe instead. 100,000 light-years (the size of a moderately large galaxy) could be a candidate for this diameter, or perhaps something smaller would do.

They are regularly found in science fiction as a means of storing objects in such a way that they cannot harm things within the main universe.

A Pocket universe is either a synonymous of a Microverse or a sub-type of it that is also self-contained.