echinoderm

From French échinoderme, corresponding to echino- +‎ -derm, after plural of 18th-century Latin echinoderma.

echinoderm (plural echinoderms)

1. An animal of the phylum Echinodermata, comprising radially symmetric, spiny-skinned marine animals including seastars, sea urchins, sea cucumbers, crinoids, and sand dollars. [from 19th c.]
   • 2012, Caspar Henderson, The Book of Barely Imagined Beings, 2013 edition, Granta Books, page 47:

     Many echinoderms are still bilateral as larvae, and swim freely in the ocean like baby fish.