"Velocity dispersion" refers to the degree of variation or spread in the speeds or velocities of objects within a group or population. It measures how much the individual velocities differ from the average velocity. Full definition
The width of a spectral line reflects velocity dispersion of the gas and shows up due to the Doppler effect caused by a distribution of the velocities of gas molecules. (sciencedaily.com)
A paper, titled «A High Stellar Velocity Dispersion and ~ 100 Globular Clusters for the Ultra Diffuse Galaxy Dragonfly 44,» describing their findings was published in the journal Astrophysical Journal Letters on Thursday. (ibtimes.com)
«If you really want to have a precise mass measurement of the black hole in a specific galaxy, you'd better use the slightly more cumbersome velocity dispersion method,» Ferrarese says. (sciencemag.org)