non-dispersive wave

A non-dispersive wave is a wave whose individual components propagate at the same velocity, regardless of their wavelength. This means that the wave's speed is constant and does not depend on its frequency or wavelength.1

In contrast, dispersive waves travel at velocities that vary with their wavelengths. For example, light passing through a prism is dispersive because different wavelengths (colors) of light are refracted at slightly different angles, causing the light to spread out into a spectrum.1

In mechanics, waves in shallow water are considered non-dispersive when their wavelength is much greater than the water depth and their amplitude is much less than the depth. In such cases, the wave speed is constant and depends only on the water depth.2