1. In a propagation medium consisting of a dispersion of scattering particles, the situation whereby the electromagnetic field in the vicinity of any particle is unaffected by scattering from the other particles. Then the total scattered field is just the sum of the fields scattered by the individual particles, each of which is acted on by the external field in isolation from the other particles. 2. The assumption that the total scattered field from a dispersion of scattering particles is the sum of the fields scattered by the individual particles. Whether single scattering is a good approximation depends on the characteristics of the particles, the wavelength of the radiation, and the way the scattered field is measured. It is more likely to be a good approximation for particles in dilute concentration that are small compared with the wavelength, and for experiments in which the beamwidth of the detector is narrow. The assumption of single scattering underlies the interpretation of most weather radar and wind profiler observations. For lidar, single scattering is said to occur when a transmitted photon experiences just one scattering event before returning to the receiver. Compare multiple scattering.