As·te`ri·oid'e·aAs`ter*id'e*a noun plural [ New Latin , from Greek 'asteri`as + -oid . See Asterias .] (Zoology) A class of Echinodermata including the true starfishes. The rays vary in number and always have ambulacral grooves below. The body i... Found on http://www.encyclo.co.uk/webster/A/135