sludge

noun

ˈsləj 

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 

adjective

Synonyms

• guck
• gook
• mire
• muck
• mud
• ooze
• slime
• slop
• slush

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

There's a Lawrenceville location, too. ☕️ Pro tip: Sip slowly to avoid a mouthful of finely ground sludge at the bottom of the cup. —Ryan Deto, Axios, 24 Feb. 2025

Now, the agency recycles sludge on more than 17,000 acres of private farmland in North and South Carolina, Frost confirmed. —Mary Ramsey, Charlotte Observer, 19 Feb. 2025

Naharin offers little context apart from a silver pail of dark sludge methodically smeared across the dancers’ faces, chests and thighs. —Lauren Warnecke, Chicago Tribune, 14 Feb. 2025

Modern incinerators are used to burn sludge, reducing 95% of the material into ash and exhaust. —Douglas Hanks, Miami Herald, 7 Feb. 2025

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

Rhymes for sludge

• budge
• drudge
• frage
• fudge
• grudge
• judge
• mudge
• nudge
• rudge
• smudge
• trudge
• adjudge

Kids Definition

sludge

noun

ˈsləj 

1

: mud, mire

2

: a muddy or slushy mass

especially : solid matter produced by water and sewage treatment processes

sludgy

ˈsləj-ē 

adjective

Medical Definition

sludge

1 of 2 noun

ˈsləj 

: 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