Supercluster

A supercluster is a huge group of galaxies spanning millions of light years. In reality, each supercluster contains multiple clusters, but in Nested they simply contain galaxies.

Found Inside
Superclusters are found inside universes in groups of around twenty.

Contains
Each supercluster contains about 10-20 galaxies.

Naming
Every supercluster is called "galactic supercluster". This is presumably to distinguish it from other clusters.