flat·​worm | \ ˈflat-ˌwərm How to pronounce flatworm (audio) \

Definition of flatworm

: any of a phylum (Platyhelminthes) of soft-bodied usually much flattened acoelomate worms (such as the planarians, flukes, and tapeworms)

called also platyhelminth

Examples of flatworm in a Sentence

Recent Examples on the Web Plants, roundworms, flatworms and insects use RNA to carry signals through their tissues, and perhaps further. Quanta Magazine, "RNA’s Secret Life Outside the Cell," 8 Nov. 2013 In nature, the organisms that exhibit it are thought to be in other groups only, like flatworms. Caroline Delbert, Popular Mechanics, "Mammalian Cells Are More Mysterious Than We Thought," 30 Dec. 2019 With the camera on, doctors immediately found the source of the problem: Large flatworms were seen spilling out of the bile duct into the small intestine. Beth Mole, Ars Technica, "Watch this beautifully disgusting liver fluke parasite explore man’s innards," 8 Nov. 2019 These are—as the name suggests—common flatworm parasites that typically infect domestic and wild ruminants, often sheep. Beth Mole, Ars Technica, "Watch this beautifully disgusting liver fluke parasite explore man’s innards," 8 Nov. 2019 Chop the freshwater flatworm Schmidtea mediterranea into tiny parts, and those parts can regenerate complete individuals. Quanta Magazine, "Biologists Search for New Model Organisms," 26 July 2016 The process starts all over again, as the birds' intestinal tract provides a space for the flatworm to reproduce and enter another unsuspecting host. Fox News, "Creepy 'zombie snail' flashes green and orange, freaks out hiker," 16 Aug. 2019 The human eye, Darwin argued, could have evolved from a simple light-catching patch of tissue of the kind that animals such as flatworms grow today. Quanta Magazine, "The Surprising Origins of Life’s Complexity," 16 July 2013 Tobias Boothe, a biologist at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany, uses it to visually distinguish the thousands of species of flatworms, a difficult task even for experts. Matthew Hutson, Science | AAAS, "No coding required: Companies make it easier than ever for scientists to use artificial intelligence," 31 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'flatworm.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of flatworm

1874, in the meaning defined above

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The first known use of flatworm was in 1874

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Cite this Entry

“Flatworm.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/flatworm. Accessed 21 Sep. 2020.

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More Definitions for flatworm


flat·​worm | \ ˈflat-ˌwərm How to pronounce flatworm (audio) \

Medical Definition of flatworm

: any worm of the phylum Platyhelminthes : platyhelminth especially : turbellarian

More from Merriam-Webster on flatworm

Britannica.com: Encyclopedia article about flatworm

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