| outwash [`au̇t´wäsh] GEOLOGY 1. Sand and gravel transported away from a glacier by streams of meltwater and either deposited as a floodplain along a preexisting valley bottom or broadcast over a preexisting plain in a form similar to an alluvial fan. Also known as glacial outwash; outwash drift; overwash. 2. Soil material washed down a hillside by rainwater and deposited on more gently sloping land. |