Asterioidea
As*te`ri*oid"e*a\, Asteridea \As`ter*id"e*a\, n. pl. [NL., fr. Gr. 'asteri`as + -oid. See Asterias.] (Zo["o]l.) A class of Echinodermata including the true starfishes. The rays vary in number and always have ambulacral grooves below. The body is star-shaped or pentagonal.