How are “scum,” “sludge,” “slush,” “slime,” “ooze,” “muck,” “mire,” “goo” and “gunk” different?

Sludge, slime, goo -- what's the difference?Toxic red sludge poured into a Hungarian village this week after a dam containing the chemical residue from an aluminum plant burst. At least four people were killed and dozens injured. The sludge continues to flow and threatens to contaminate the Danube River, one of Europe’s major waterways.

This tragedy poses a linguistic puzzle that, hopefully, can help us better describe the type of environmental horrors that seem to occur with increasing frequency. What words should we use to describe the substances we don’t want to think about? The stuff that is disgusting, harmful, not quite liquid but not quite solid?

Much of our vocabulary for these substances sounds funny: “gunk,” “goo,” “muck.” Let’s see if we can bring some clarity to these ambiguous terms that actually define things aren’t funny at all.

Sludge has a legal definition: “nutrient-rich, organic byproduct of the nation’s wastewater treatment process.” It can also be a “deposit at the bottom of a body of water.” Slush may be its source, but we think of this nicer-sounding word as a nicer substance, melting snow. Slush, however, can also be “waste, as fat, grease, or other refuse, from the galley of a ship.” Try not to think of that when you eat a slushee.

Slime is a general term, but traditionally describes organic matter: “a mucous substance produced by various organisms, such as fish, slugs, and fungi.”

Setting aside its use as an insult, scum specifically means “a film or layer of foul or extraneous matter that forms on the surface of a liquid.”

Ooze is a reluctant noun. The vague definition “anything that oozes” feels like a cop-out. Ooze works more effectively as a verb, anyhow.

Goo, “a thick or sticky substance,” generally describes friendlier stuff than toxic hazards, like pudding or glue. It probably derives from burgoo“thick porridge.” Gunk was originally a trademarked name of a degreasing solvent.

Muck and mire may be gross, but at least they’re made by nature. Muck is “an area of wet, swampy ground,” and mire is “a highly organic, dark or black soil, less than 50 percent combustible, often used as manure.”

After all that, want to know where “yuck” originated? Click here.

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