planaria
noun
pla·nar·ia plə-ˈner-ē-ə 
plural planaria also planarias
: any of a genus (Planaria) of 2-eyed planarian worms
broadly : planarian
Example Sentences
Recent Examples on the Web Though often no bigger than an apple seed, planaria are the envy of the animal kingdom. 
Elizabeth Pennisi, Science | AAAS, 14 June 2018 One hundred and twenty-four of the genes missing from planaria are essential to humans and mice, but the worms seem to do fine without them. John Timmer, Ars Technica, 25 Jan. 2018 More distantly related worms called planaria can be cut into multiple pieces and see each piece regrow an entirely new body. John Timmer, Ars Technica, 25 Jan. 2018 Plenty of other animals can do this — from planaria to newts. David Freeman /, NBC News, 28 Jan. 2018
Elizabeth Pennisi, Science | AAAS, 14 June 2018 One hundred and twenty-four of the genes missing from planaria are essential to humans and mice, but the worms seem to do fine without them. John Timmer, Ars Technica, 25 Jan. 2018 More distantly related worms called planaria can be cut into multiple pieces and see each piece regrow an entirely new body. John Timmer, Ars Technica, 25 Jan. 2018 Plenty of other animals can do this — from planaria to newts. David Freeman /, NBC News, 28 Jan. 2018 Word History
Etymology
New Latin, from feminine of Late Latin planarius lying on a plane, from Latin planum plane
First Known Use
1855, in the meaning defined above
Medical Definition
planaria
noun
pla·nar·ia plə-ˈnar-ē-ə, -ˈner-
1
capitalized : the type genus of the family Planariidae comprising planarian worms having two eyes
2
: any worm of the genus Planaria
broadly : planarian