a single-celled aquatic animal which has a spherical amoeba-like body with a spiny skeleton of silica. Their skeletons can accumulate as a slimy deposit on the seabed.
Three classes of the phylum Actinopoda, kingdom Protista (formerly subclass or order Radiolaria)
adjective
relating to or formed from radiolarians:radiolarian ooze
radiolarian in other Oxford dictionaries
Definition of radiolarian in the US English dictionary
