Mud's a liquid or semi-liquid mixture of water and some combination of soil, silt, and clay. Ancient mud deposits harden over geological time to form sedimentary rock such as siltstone or solid, mudrock lutites. When geological deposits of mud are formed in estuaries the resultant layers are termed bay muds. Mud's closely related to slurry and sediment. Mud, in the construction industry, refers to wet plaster, stucco, cement or other similar substances. In ceramics, the making of liquid mud (ca… (More on Mud)