meta-universe
/ˌmɛtəˈjuːnɪvəːs/noun
1A ‘universe of universes’; an assembly of universes, considered as a whole; that which contains or consists of many (potential or actual) separate universes.
2An alternative world or universe, especially one that is abstract, theoretical, or hypothetical.
Origin
1970s; earliest use found in Scientific American. From meta- + universe, in sense 1 perhaps after metagalaxy.