ˈau̇sˌtau̇sh noun
( plural austau·sche -shə)
Etymology: German, literally, exchange, from austauschen to exchange, from aus out (from Old High German ūz ) + tauschen to exchange, barter, from Middle High German tūschen, tiuschen to barter, deceive, mock, from Middle Low German tüschen, literally, to tell a lie
1. : an effect of turbulent motion in the atmosphere that is manifested by an exchange of air and water vapor molecules, together with their momentum and heat energy, from one horizontal layer to another
2. : the viscosity coefficient for horizontal flow in the atmosphere where it is affected by turbulence