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ra·di·o·lar·i·an

(rā′dē-ō-lârē-ən)

Any of various marine protozoans of the order (or phylum) Radiolaria, having rigid siliceous skeletons and spicules.

[From New Latin Radiolāria, order name, from Late Latin radiolus, diminutive of Latin radius, ray, spoke (in reference to their spicules); see RAY¹.]

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radiolarian

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

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Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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