any of the marine invertebrate animals constituting the phylum Echinodermata, characterized by tube feet, a calcite body-covering (test), and a five-part symmetrical body. The group includes the starfish, sea urchins, and sea cucumbers
Derived forms
echinodermal (eˌchinoˈdermal) or echinodermatous (eˌchinoˈdermatous)
adjective
echinoderm in American English
(iˈkaɪnoʊˌdɜrm; ˈɛkɪnoʊˌdɜrm)
noun
any of a phylum (Echinodermata) of marine animals with a water-vascular system, andusually with a hard, spiny skeleton and radial body, including the starfishes and sea urchins