pla·​nar·​i·​an | \ plə-ˈner-ē-ən How to pronounce planarian (audio) \

Definition of planarian

: triclad especially : any of various dark-colored freshwater triclad flatworms (family Planariidae) with two eyespots and a triangular head

Examples of planarian in a Sentence

Recent Examples on the Web Severance occurs when the tail tip adheres to the substratum and the rest of the planarian pulls away. Chris Ciaccia, Fox News, "Massive 18-inch hammerhead worms are invading France," 23 May 2018 For the planarian, the researchers were able to identify roughly 1,000 likely genes that are probably specific to these organisms. John Timmer, Ars Technica, "A salamander with a genome 10 times the size of ours regrows lost limbs," 25 Jan. 2018 That's exactly what happened with earlier attempts to sequence the planarian and axolotl genomes. John Timmer, Ars Technica, "A salamander with a genome 10 times the size of ours regrows lost limbs," 25 Jan. 2018 Reader Terri Shofner then alerted us to Ho's video of the odd-looking creature, which experts say is likely an unknown species of the genus Bipalium, known by the common names hammerhead worm and broadhead planarian. Liz Langley, National Geographic, "Watch a Mysterious Worm With an Anus for a Mouth," 15 July 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'planarian.' 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 planarian

1854, in the meaning defined above

History and Etymology for planarian

New Latin Planaria

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The first known use of planarian was in 1854

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Cite this Entry

“Planarian.” Dictionary, Merriam-Webster, Accessed 25 Feb. 2021.

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More Definitions for planarian


pla·​nar·​i·​an | \ -ē-ən How to pronounce planarian (audio) \

Medical Definition of planarian

: any of the family Planariidae or order Tricladida comprising small soft-bodied ciliated mostly aquatic turbellarian worms

Other Words from planarian

planarian adjective

More from Merriam-Webster on planarian

Britannica English: Translation of planarian for Arabic Speakers Encyclopedia article about planarian

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