# sludge

> English word · Noun · IPA /slʌd͡ʒ/ · frequency rank #21,661

## Definitions
1. Solids separated from suspension in a liquid.
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. Ellipsis of sludge metal.
6. Institutional policies that introduce tedium and inefficiency in processes.

## Etymology
From Middle English slugge, sluche (“mud, mire”), probably an alteration of Middle English sliche, slicche ("mud, slush, tar"; whence Modern English slitch), from Old English *sliċ, from Proto-West Germanic *sliki, *slīk, from Proto-Germanic *slikiz, *slīką (“mud, slush”). Cognate with Dutch slijk, German Schlick. Compare also slush.

## Easily confused with
- **slug** (https://plainspell.com/en/vs/sludge-vs-slug)
- **surge** (https://plainspell.com/en/vs/sludge-vs-surge)
- **slung** (https://plainspell.com/en/vs/sludge-vs-slung)
- **smudge** (https://plainspell.com/en/vs/sludge-vs-smudge)
- **sluice** (https://plainspell.com/en/vs/sludge-vs-sluice)
- **splurge** (https://plainspell.com/en/vs/sludge-vs-splurge)
- **slugger** (https://plainspell.com/en/vs/sludge-vs-slugger)
- **smudged** (https://plainspell.com/en/vs/sludge-vs-smudged)
- **slide** (https://plainspell.com/en/vs/slide-vs-sludge)
- **slade** (https://plainspell.com/en/vs/slade-vs-sludge)
- **sledge** (https://plainspell.com/en/vs/sledge-vs-sludge)

## Common misspellings (9)
`lsudge`, `slduge`, `slludge`, `sluddge`, `sludeg`, `sludgge`, `slugde`, `ssludge`, `suldge`

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/sludge