sludge
Americannoun
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mud, mire, or ooze; slush.
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a deposit of ooze at the bottom of a body of water.
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any of various more or less mudlike deposits or mixtures.
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the sediment in a steam boiler or water tank.
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broken ice, as on the sea.
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a mixture of some finely powdered substance and water.
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sediment deposited during the treatment of sewage.
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Also called activated sludge. Bacteriology. sewage sediment that contains a heavy growth of microorganisms, resulting from vigorous aeration.
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a fine, mudlike powder produced by a mining drill.
noun
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soft mud, snow, etc
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any deposit or sediment
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a surface layer of ice that has a slushy appearance
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(in sewage disposal) the solid constituents of sewage that precipitate during treatment and are removed for subsequent purification
Other Word Forms
Noun Inflected Forms
Etymology
Origin of sludge
First recorded in 1640–50; variant of dialectal slutch, slitch, Middle English slich “slime, wet mud” (compare its derivative slucched “muddy”); apparently of expressive origin
Explanation
Sludge is thick, damp, almost sticky stuff. If your friend dares you to climb through an old sewer pipe, you might want to check first to see if it's full of sludge. Sludge is often used to talk about the byproduct of a process like sewage treatment or oil refining, but you can use it for any viscous goop. Sludge floating in your fish tank is a sign that you should clean the water, and sludge inside a car's engine can affect the way the car runs. Sludge is a bit of a mystery — it may come from the Middle English slutch, "mud," or might be related to slush.
Vocabulary lists containing sludge
A Long Walk to Water
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The Devil's Arithmetic
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The Omnivore's Dilemma
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Sludge boats were designed to take the strain from Britain's overburdened Victorian sewage system.
From BBC • Nov. 25, 2023
Publications like Grim’s Intercept and Sludge—yes, Sludge, it’s a good site—have run down those names, documenting each known donor’s professional background and other activity.
From Slate • Jul. 4, 2023
Their 2016 debut, “I, Gemini,” was a frenetic album of distorted, twitchy pop with song titles like “Eat Shiitake Mushrooms” and “Chocolate Sludge Cake.”
From New York Times • Apr. 20, 2022
According to Sludge, Williams, who boasts a net worth of $27.7 million, took in over $1.4 million for his JRW Corporation, valued $50 million back in 2019.
From Salon • Sep. 25, 2021
A swirling human figure erupted from the sand—Leo’s least favorite goddess, the Mistress of Mud, the Princess of Potty Sludge, Gaea herself.
From "The House of Hades" by Rick Riordan
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
