(1) A slimy sticky mixture of solid material with a liquid and especially water; especially soft wet earth. (2) Also, wet soft earth composed predominantly of clay and silt: fine mineral sediments less than 0.074 mm (0.0029 inch) in diameter.
MUD
Meaning of MUD in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012