An animal of the phylum Echinodermata, comprising radially symmetric, spiny-skinned marine animals including seastars, sea urchins, sea cucumbers, crinoids, and sand dollars.

plural of echinoderm

(zoology) Relating or belonging to the echinoderms.

Relating to echinoderms

(zoology) Relating to Echinodermata; echinodermal.