Stellar density is the average number of stars within a unit volume.
Typically, the volume used by astronomers to describe the stellar density is a cubic parsec (pc3).
In the solar neighborhood, this value can be determined from surveys of nearby stars, combined with estimates of the number of faint stars that may have been missed.
[1] The locations within the Milky Way that have the highest stellar density are the galactic core and the center of globular clusters.
[2] In the solar neighborhood, the stellar density of a star cluster must be greater than 0.08 MSun pc−3 in order to avoid tidal disruption.