sludge

noun

ˈsləj How to pronounce sludge (audio)
Synonyms of sludgenext
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
3
: slush sense 5
sludgy
ˈslə-jē How to pronounce sludge (audio)
adjective

Synonyms of 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Residents sat in homes with walls washed away by the floods, shoveling sludge-like mud and rubble off balconies or window frames. — Victoria Milko, Los Angeles Times, 30 Aug. 2026 Venezuelan oil, by contrast, is heavy, sour sludge, which can more easily be distilled into asphalt, industrial oils, diesel and jet fuel. — David Goldman, CNN Money, 29 Aug. 2026 Pumping at high speeds creates a suction vortex (upconing) that violently draws heavy sludge into the production stream, fouling piping and destroying surface pumps. — Siddharth Misra, Fortune, 25 Aug. 2026 Related Stories The report noted that sludge remained Saitex’s primary source of waste in 2025, and that the company repurposed 40 percent of that waste to produce bricks for garden walkways and concrete blocks for retaining walls. — Jennifer Bringle, Footwear News, 21 Aug. 2026 See All Example Sentences for sludge

Word History

Etymology

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

First Known Use

15th century, in the meaning defined at sense 1

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

Rhymes for sludge

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Browse Nearby Words

slud
sludge
sludge acid
See all Nearby Words

Cite this Entry

“Sludge.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sludge. Accessed 1 Sep. 2026.

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Kids Definition

sludge

noun
ˈsləj How to pronounce sludge (audio)
1
: mud, mire
2
: a muddy or slushy mass
especially : solid matter produced by water and sewage treatment processes
sludgy
ˈsləj-ē How to pronounce sludge (audio)
adjective

Medical Definition

sludge

1 of 2 noun
ˈsləj How to pronounce sludge (audio)
: a semisolid precipitated mass or deposit
biliary sludge
especially : sludged blood

sludge

2 of 2 intransitive verb
sludged; sludging
: to form sludge
positions that cause blood to sludge—L. K. Altman
Last Updated: - Updated example sentences
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