the velocity of finite numbers of waves undergoing simple harmonic motion, equal to the phase velocity when it does not vary with the wavelengths of the waves. The group velocity of the set of waves produced in water when a stone is dropped is less than the velocity of the individual waves.
Surface-wave group-velocity tomography is an efficient way to obtain images of the group velocity over a test area.
In this interpretation a peak occurs for a maximum energy arrival and thus corresponds to the group velocity along its path.
On the group velocity of symmetric and upwind numerical schemes.
British Dictionary definitions for group velocity
(physics) the speed at which energy is propagated in a wave. This is the quantity determined when one measures the distance which the radiation travels in a given time. In a medium in which the speed increases with wavelength the group speed is less than the phase speed, and vice versa