Any of numerous radially symmetrical marine invertebrates of the phylum Echinodermata,which includes the starfishes,sea urchins,and sea cucumbers,having an internal calcareous skeleton and often covered with spines.

• 棘皮动物，任一种属于棘皮动物门的许多呈辐射对称状的海生无脊椎动物，包括海盘车、海胆和海参，内部骨架含钙，常覆盖有棘针。