You searched for: “superclusters
supercluster (s) (noun), superclusters (pl)
An association of clusters of galaxies.

Superclusters are large assemblages of smaller galaxy groups and clusters, and are among the largest structures of the cosmos.

The existence of superclusters indicates that the galaxies in our Universe are not uniformly distributed; most of them are grouped together in groups and clusters, with groups containing up to fifty galaxies and clusters up to several thousand.

Those groups and clusters and additional isolated galaxies in turn form even larger structures called "superclusters".