Sludge
/slʌdʒ/noun
Thick, muddy, viscous soft matter or residue.
Did you know?The earliest English forms of *sludge* were linked to swampy, muddy ground and sticky sediment, not just industrial waste, so the word has always carried the feeling of something half-dead and sinking.
Etymological Timeline
Proto-Germanic
PGmc
*slud- / *slut-
“A muddy, wet, or slushy mass; something soft and slippery.”
Old English
OE
slydge / sludge
“Mud, mire, or a boggy, oozy substance.”
Middle English
ME
sludge
“Thick mud or soft mire, especially in wet ground.”
16th–17th Century
English
sludge
“Muddy sediment or thick, dirty matter.”
19th Century
English
sludge
“Industrial residue, sewage, or thick waste material.”