What is the primary defining feature used to delineate the Laniakea Supercluster structure?

The collective flow of matter toward the Great Attractor

The Laniakea Supercluster represents a newer classification system in cosmology, shifting focus from older methods based purely on static proximity or gravitational grouping like the Virgo Supercluster. Laniakea is fundamentally defined by the velocity field—the bulk flow of matter. This means that all constituent galaxies within Laniakea are observed to be moving or flowing toward a common gravitational center, which is identified as the Great Attractor. This dynamical definition provides a more physically meaningful grouping on the largest scales measured for our local volume of space, distinguishing it from older, potentially flatter or less dynamically coherent structures.