\ ˈsləj How to pronounce sludge (audio) \

Definition of sludge

1 : mud, mire especially : a muddy deposit (as on a riverbed) : ooze
2 : a muddy or slushy mass, deposit, or sediment: such as
a : precipitated solid matter produced by water and sewage treatment processes
b : muddy sediment in a steam boiler
c : a precipitate or settling (such as a mixture of impurities and acid) from a mineral oil

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Other Words from sludge

sludgy \ ˈslə-​jē How to pronounce sludge (audio) \ adjective

Synonyms for sludge


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Examples of sludge in a Sentence

after a day of heavy rain, the fairgrounds had turned into pure sludge I can't bring myself to read that sludge.
Recent Examples on the Web Four residents were trapped in their homes by the brown sludge and had to be freed by Orange County firefighters, Doran said. Lila Seidman, Los Angeles Times, "Mudslide evacuations remain in O.C. as incoming storm keeps fears high," 11 Mar. 2021 Their older brother, Robbie, sometimes rakes them out as a courtesy to others, along with the tiny water weeds that grow if allowed, and puts the resulting sludge into a large zinc washtub, after which its fate is unknown to Nell. Margaret Atwood, The New Yorker, "Old Babes in the Wood," 19 Apr. 2021 In that time, the plant produced 22 million tons of phosphorus sludge—which is toxic if absorbed, ingested, or inhaled and explodes upon exposure to air—that was then stored on the Fort Hall Reservation, the present home of the tribal nation. Nick Martin, The New Republic, "Indian Country Refuses to Be Corporate America’s Dumping Ground," 12 Jan. 2021 Before this cease and desist order, Denali had already been issued a warning letter and two notices of violations for its sludge operations in Marshall, Lawrence and Colbert Counties, according to ADEM records. Dennis Pillion |, al, "Alabama shuts down poultry waste sludge operation north of Birmingham," 11 Mar. 2021 Rogers Water Utilities also operates a sludge dryer and has budgeted $19 million for two new units, said Brent Dobler, superintendent. Laurinda Joenks, Arkansas Online, "Springdale wants sludge dryer completed," 27 Feb. 2021 Coal ash, a toxic substance produced by coal power plants that is often stored as sludge in special ponds, have been particularly exposed. New York Times, "Texas Blackouts Point to Coast-to-Coast Crises Waiting to Happen," 20 Feb. 2021 Deblais and colleagues put a blob of these sludge worms into a special device to measure the viscosity of the liquid around them. Eric Niiler, Wired, "Researchers Are Studying These Worm Blobs to Build Robots," 17 Feb. 2021 While a year of lockdown has left many of us feeling down, the song serves as a divine source of encouragement to power through the sludge. Katie Bain, Billboard, "First Spin: The Week's Best New Dance Tracks From Jungle, Zhu, Elkka, Floating Points & More," 26 Mar. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sludge.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of sludge

15th century, in the meaning defined at sense 1

History and Etymology for sludge

Middle English slugge, perhaps alteration of slicche mud, slush; akin to Old High German slīh mire

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Time Traveler for sludge

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The first known use of sludge was in the 15th century

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Statistics for sludge

Last Updated

5 May 2021

Cite this Entry

“Sludge.” Dictionary, Merriam-Webster, Accessed 12 May. 2021.

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More Definitions for sludge



English Language Learners Definition of sludge

: thick, soft, wet mud
: a soft, thick material that is produced in various industrial processes (such as in the treatment of sewage)
: a thick material that can form in the oil in an engine and cause engine problems


\ ˈsləj How to pronounce sludge (audio) \

Kids Definition of sludge

: a soft muddy mass resulting from sewage treatment


\ ˈsləj How to pronounce sludge (audio) \

Medical Definition of sludge

 (Entry 1 of 2)

: a semisolid precipitated mass or deposit biliary sludge especially : sludged blood
sludged; sludging

Medical Definition of sludge (Entry 2 of 2)

: to form sludge positions that cause blood to sludge— L. K. Altman

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