pond scum
noun
1
: any of various algae (especially spirogyra) or cyanobacteria
2
: a mass of tangled filaments of algae or cyanobacteria in stagnant waters
Examples of pond scum in a Sentence
Recent Examples on the Web
Their small bodies are tricky to differentiate from pond scum or sticky clumps of algae in the dark.
—
Sophie Hartley,
IndyStar,
9 Sep. 2025
Certain minerals could've preserved that pond scum, forming what scientists call stromatolites — a kind of layered rock that's essentially a fossil.
—
Eric Betz,
Discover Magazine,
10 Feb. 2021
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Sophie Hartley,
IndyStar,
9 Sep. 2025
Certain minerals could've preserved that pond scum, forming what scientists call stromatolites — a kind of layered rock that's essentially a fossil.
—
Eric Betz,
Discover Magazine,
10 Feb. 2021
Cite this Entry
“Pond scum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pond%20scum. Accessed 4 Jul. 2026.
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