pond scum


: any of various algae (especially spirogyra) or cyanobacteria
: a mass of tangled filaments of algae or cyanobacteria in stagnant waters

Examples of pond scum in a Sentence

Recent Examples on the Web Yet the evidence for cogitating pond scum grows daily. Rowan Jacobsen, Scientific American, 21 Sep. 2020 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 And perhaps the most intriguing possibility is that Jezero Crater may have once been home to microbial mats, like pond scum forming at a lake's edge. Eric Betz, Discover Magazine, 10 Feb. 2021 Peer at the cell structure in an onion's skin, examine a human hair or look at the busy microbial world of pond scum. Citizen Science Salon, Discover Magazine, 19 Mar. 2020 Treehugger reports: The pond scum in question is microcystin-LR (MC-LR), which makes water unsafe for drinking, swimming and fishing in many parts of the world. Smriti Rao, Discover Magazine, 10 Mar. 2010 After a lovely day of rolling in the grass, digging in the dirt, playing in mud or pond scum, bathe your pet with Calm Shampoo, which is a one-of-a-kind day at the spa for Rocco & Roxie Supply Co.'s dogs. Amber Smith, Discover Magazine, 22 Oct. 2022 The plaque on your teeth is a biofilm; so too are infections on catheters, the slimy green of pond scum and the gunk clogging your bathtub drain. Carrie Arnold, Quanta Magazine, 2 Nov. 2022 In Earth's earliest fossil record, scientists study fossilized pond scum rather than bones or shells. Ashley Strickland, CNN, 3 Mar. 2021

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'pond scum.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1864, in the meaning defined at sense 1

Time Traveler
The first known use of pond scum was in 1864

Dictionary Entries Near pond scum

Cite this Entry

“Pond scum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pond%20scum. Accessed 18 Jun. 2024.

Kids Definition

pond scum

: spirogyra
also : any of various related algae
: a mass of tangled threads of algae in still water

More from Merriam-Webster on pond scum

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!