An Etymological Dictionary of Astronomy and Astrophysics

A → supercluster of galaxies that includes our → Local Group and about 300 to 500 known → galaxy clusters and groups. Also called → Local Supercluster. If approximated as round, it has a diameter of 12,000 km s^-1 in units of the → cosmic expansion or 160 megaparsecs, and encompasses about 10¹⁷ → solar masses.
Our Local Group lies toward the outer regions of Laniakea. Its main components are the four previously known superclusters:

→ Virgo supercluster (the part where the → Milky Way resides),
Hydra-Centaurus Supercluster (including the → Great Attractor, Antlia Wall, known as Hydra Supercluster, → Centaurus supercluster), Pavo-Indus Supercluster, and Southern Supercluster (including Fornax Cluster, Dorado and Eridanus clouds).

The most massive galaxy clusters of Laniakea are Virgo, Hydra, Centaurus, Abell 3565, Abell 3574, Abell 3521, Fornax, Eridanus, and Norma. The Laniakea supercluster was discovered by Tully et al. (2014, Nature 513, 71).

See also: From the Hawaiian words lani “heaven,” and akea “spacious, immeasurable;” → supercluster.