planarian
noun
pla·nar·i·an
plə-ˈner-ē-ən 
: 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
This capacity is all too evidently lacking in humans—so how do planarians do it?
—
Philip Ball, Scientific American, 18 Apr. 2023
Even a small part of a planarian can regenerate into a full worm with the typical shape and proportions.
—Philip Ball, Scientific American, 18 Apr. 2023
Cut off a planarian's head, and the creature will simply sprout a new one in its place.
—Marla Broadfoot, Discover Magazine, 25 Nov. 2015
So how did the the planarian lose its centrosomes?
—Elizabeth Preston, Discover Magazine, 10 Jan. 2012
If one animal could become an honorary superhero, my vote would be for the planarian.
—Seriously Science, Discover Magazine, 15 July 2013
Even so, this planarian and its beady eyespots is cute enough to take your breath away.
—Christie Wilcox, Discover Magazine, 3 Sep. 2015
With no new ones to replace them, the planarian has a few weeks to live.
—Ed Yong, Discover Magazine, 12 May 2011
Researchers led by Wallace Marshall at the University of California, San Francisco, wanted to know how centrosomes were involved in the amazing regenerative abilities of this planarian.
—Elizabeth Preston, Discover Magazine, 10 Jan. 2012
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Philip Ball, Scientific American, 18 Apr. 2023
Even a small part of a planarian can regenerate into a full worm with the typical shape and proportions.
—Philip Ball, Scientific American, 18 Apr. 2023
Cut off a planarian's head, and the creature will simply sprout a new one in its place.
—Marla Broadfoot, Discover Magazine, 25 Nov. 2015
So how did the the planarian lose its centrosomes?
—Elizabeth Preston, Discover Magazine, 10 Jan. 2012
If one animal could become an honorary superhero, my vote would be for the planarian.
—Seriously Science, Discover Magazine, 15 July 2013
Even so, this planarian and its beady eyespots is cute enough to take your breath away.
—Christie Wilcox, Discover Magazine, 3 Sep. 2015
With no new ones to replace them, the planarian has a few weeks to live.
—Ed Yong, Discover Magazine, 12 May 2011
Researchers led by Wallace Marshall at the University of California, San Francisco, wanted to know how centrosomes were involved in the amazing regenerative abilities of this planarian.
—Elizabeth Preston, Discover Magazine, 10 Jan. 2012
Cite this Entry
“Planarian.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/planarian. Accessed 27 Feb. 2025.
Copy CitationKids Definition
planarian
noun
pla·nar·i·an
plə-ˈnar-ē-ən
-ˈner-
: any of an order of small soft-bodied mostly water-dwelling flatworms having cilia
especially
: one living in fresh water and having two eyespots and a triangular head
Medical Definition
planarian
noun
pla·nar·i·an
-ē-ən
: any of the family Planariidae or order Tricladida comprising small soft-bodied ciliated mostly aquatic turbellarian worms
planarian
adjective
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