1. The change in the direction of energy travel because of collisions or inhomogeneity or anisotropy of the medium. 2. The irregular and diffuse dispersion of energy caused by inhomogeneities in the medium through which the energy is traveling. A perturbation of a uniform field caused by irregularities in the medium. A scattered wavefield is the wavefield that remains when the primary wavefield is subtracted from the total wavefield.