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radiolarian

[ rey-dee-oh-lair-ee-uhn ]
/ ˌreɪ di oʊˈlɛər i ən /
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noun

any minute, marine protozoan of the class Radiolaria, or, in some classification schemes, the superclass Actinopoda, having an amebalike body with radiating, filamentous pseudopodia and a usually elaborate outer skeleton.

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Origin of radiolarian

1875–80; <New Latin Radiolari(a) name of the group (Latin radiol(us) a small beam, equivalent to radi(us) radius + -olus-ole1 + -aria-aria) + -an
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

British Dictionary definitions for radiolarian

radiolarian
/ (ˌreɪdɪəʊˈlɛərɪən) /

noun

any of various marine protozoans constituting the order Radiolaria, typically having a siliceous shell and stiff radiating cytoplasmic projections: phylum Actinopoda (actinopods)
C19: from New Latin Radiolaria, from Late Latin radiolus little sunbeam, from Latin radius ray, radius
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for radiolarian

radiolarian
[ rā′dē-ō-lârē-ən ]

Any of various marine protozoans of the group Radiolaria, having rigid skeletons usually made of silica. The skeletons are usually spherically symmetrical and structurally complex, containing elaborate patterns of perforations (through which pseudopods extend) and often spicules. Skeletal remains of radiolarians sink to form ooze on the ocean floor, and prehistoric radiolarian ooze has fossilized to become chert and flint.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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