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.
Origin of group velocity
First recorded in 1885–90
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019