schmutzdecke
n.— «Periodically the top layer of sand (approximately 25 to 100m deep) needs to be removed from the slow sand filters together with the associated biological accumulation (“schmutzdecke”) for cleaning.» —“Tender—Department Of The Environment For Northern Ireland Water Executive—Central Design Unit” Contract Journal January 27, 1994. (source: Double-Tongued Dictionary)
Further reading
Rose in Lebanon, Virginia recalls a phrase passed down from her great-grandmother: The night before the first day of school, parents would come into the children’s bedroom and say in a singsong voice: School butter, school butter. This...
An upscuddle, also spelled upscuttle, is defined in both the Dictionary of American Regional English and the Dictionary of Southern Appalachian English (Bookshop|Amazon) as a type of quarrel. A 1913 reference uses the term this way: “If they...