wash·out / ˈwäshˌout; ˈwôsh-/ • n. 1. [usu. in sing.] inf. an event that is spoiled by constant or heavy rain. ∎  a disappointing failure: the film was a washout.2. a breach in a road or railroad track caused by flooding. ∎  Geol. a channel cut into a sedimentary deposit by rushing water and filled with younger material.3. Med. the removal of material or a substance from the body or a part of it, either by washing with a fluid, or by allowing it to be eliminated over a period.

washout Nutrients that dissolve in atmospheric water droplets and are brought to the surface in precipitation. See wetfall; compare rainout.