echinoidea Meaning, Definition & Usage

  1. noun sea urchins and sand dollars
    class Echinoidea.

WordNet

Ech`i*noi"de*a noun plural
Etymology
NL. See Echinus, and -oid.
Definitions
  1. (Zoöl.) The class Echinodermata which includes the sea urchins. They have a calcareous, usually more or less spheroidal or disk-shaped, composed of many united plates, and covered with movable spines. See Spatangoid, Clypeastroid. Written also Echinidea, and Echinoida.

Webster 1913