schmutzdecke n. a naturally occurring gelatinous layer of living biological matter on a sand-based water filter, for which it provides additional filtration. Editorial Note: Occasionally spelled in English as “schmutzedecke” or “smutzdecke.” Etymological Note: German schmutz ‘dirt’ + decke ‘covering.’ (source: Double-Tongued Dictionary)
Further reading
What kind of book do people ask for most often in prison? Romance novels? No. The Bible? No. The most requested books by far are … dictionaries! A number of volunteer organizations gather and distribute used dictionaries to help inmates with...
Twice a day the River Thames recedes, revealing a muddy shoreline. Hobbyists known as mudlarks stroll the surface searching for objects that have found their way into the river over the centuries, everything from ancient Roman jewelry to modern...