Crinoidea \Cri*noid"e*a\ (kr[-i]*noid"[-e]*[.a]), n. pl. [NL., from Gr. kri`non lily + -oid: cf. F. crino["i]de.] (Zool.) A large class of Echinodermata, including numerous extinct families and genera, but comparatively few living ones. Most of the fossil species, like some that are recent, were attached by a jointed stem. See {Blastoidea}, {Cystoidea}, {Comatula}. [1913 Webster]