supercluster

A supercluster is a cluster of galaxy groups and clusters. Typical size is several hundred million light-years across, and some 10¹⁷ solar masses.

Whether a given supercluster is gravitationally bound is often a subject of repeated analysis, often concluding that particular superclusters are not. Given that, the term indicates "a grouping of clusters, which may or may not be gravitationally bound", which some consider to be of little use, though it is accepted that galaxy clusters are generally gathered in groups rather than spread randomly. A level up from superclusters are galaxy filaments, galaxy walls or galaxy sheets, and supercluster complexes.

The term Local Supercluster has long been used for the Virgo Supercluster, which includes the Local Group (with the Milky Way) as well as the Virgo Cluster and is thought to contain 47,000 galaxies. Laniakea Supercluster has been declared a larger supercluster that includes the Virgo Supercluster, so the term Local Supercluster could be used to mean it instead.