sludges

Noun

sludge (countable and uncountable, plural sludges)

1. Solids separated from suspension in a liquid.
   • Floods in northern India, mostly in the small state of Uttarakhand, have wrought disaster on an enormous scale.[…]Rock-filled torrents smashed vehicles and homes, burying victims under rubble and sludge.2013 June 29, “High and wet”, in The Economist, volume 407, number 8842, page 28

   Synonyms:

   mire, mud, ooze, slush

2. A residual semi-solid material left from industrial, water treatment, or wastewater treatment processes.
3. A sediment of accumulated minerals in a steam boiler.
4. A mass of small pieces of ice on the surface of a water body.
5. (behavioral science) Institutional policies that introduce tedium and inefficiency in processes.
   • In the 2008 best seller Nudge, the legal scholar Cass R. Sunstein and the economist Richard H. Thaler marshaled behavioral-science research to show how small tweaks could help us make better choices. An updated version of the book includes a section on what they called “sludge”—tortuous...[2025 June 29, Chris Colin, “That Dropped Call With Customer Service? It Was on Purpose.”, in The Atlantic, retrieved 29 Jun 2025, Ideas

See all 8 meanings of sludge