back·scat·ter / ˈbakˌskatər/ • n. Physics deflection of radiation or particles through an angle of 180°. ∎  radiation or particles that have been deflected in this way. ∎ Photog. light from a flashgun or other light source that is deflected directly into a lens: backscatter causes an underexposed picture with a blizzard effect.• v. [tr.] Physics deflect (radiation or particles) through an angle of 180°: [as adj.] (backscattered) backscattered sound reaches the sonar receiver.

backscatter When a surface is illuminated by a radar beam, a portion of the energy is reflected back to the antenna (‘specular reflection’). A further portion is scattered back in the same way as light is scattered from non-reflective surfaces. The proportion scattered is controlled by factors such as the roughness and dielectric properties of the surface, and the wavelength of the incident beam.