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Any of various small, chiefly freshwater flatworms of the order Tricladida, having a soft, broad, ciliated body, a three-branched digestive cavity, and the ability to regenerate body parts.

[From New Latin Plānāria, genus name, from feminine of Late Latin plānārius, on level ground, from plānus, flat; see pelə- in Indo-European roots.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Animals) any free-living turbellarian flatworm of the mostly aquatic suborder Tricladida, having a three-branched intestine
[C19: from New Latin Plānāria type genus, from Late Latin plānārius level, flat; see plane1]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(pləˈnɛər i ən)

any of various free-swimming, mostly freshwater flatworms, having an undulating or sluglike motion.
[1885–60; < New Latin Planari(a) a flatworm genus (n. use of feminine of Late Latin plānārius level, on level ground; taken to mean “flat”; see plane1, -ary) + -an1]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.planarian - free-swimming mostly freshwater flatwormsplanarian - free-swimming mostly freshwater flatworms; popular in laboratory studies for the ability to regenerate lost parts
flatworm, platyhelminth - parasitic or free-living worms having a flattened body
class Turbellaria, Turbellaria - free-living flatworms
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
This isn't a total expiration - because Capita resembles the planarian worm, whose exceptional regenerative abilities enable it to regrow even its own severed head.
Gamma-aminobutyric acid in the nervous system of a planarian. J.
Planarian worms, jellyfish, and sea anemones can actually regenerate their entire bodies after being cut in half.
WHAT sort of creature is a planarian? WHERE in Europe can you visit Phoenix Park?
Genotoxicity evaluation of ionic liquid 1-octyl-3-methylimidazolium bromide in freshwater planarian Dugesia japonica using RAPD assay.
For more than a century, scientists have witnessed the effects of this cellular marvel, which enables creatures such as the planarian flatworm to perform death-defying feats like re-growing a severed head.
Let's start in the 1950s, when Dr James V McConnell conducted a controversial experiment with planarian worms.
She took the flaccid worm, the planarian, and got into the car.
In one scene, the stage directions call for film footage to be played as the characters, The Rose, The Wolf, General Planarian, and The Shark, march around the stage.
Sanchez Alvarado, "SMEDWI-2 is a PIWI-like protein that regulates planarian stem cells," Science, vol.