the washing away of soil or other material by rain
rainwash in American English
(ˈreinˌwɑʃ, -ˌwɔʃ)
noun
material eroded or swept away by rain
Word origin
[1875–80; rain + wash]This word is first recorded in the period 1875–80. Other words that entered Englishat around the same time include: authoritarian, knockabout, neoclassic, slime mold, weekend