The Collaborative International Dictionary of English v.0.48:

Radiata \Ra`di*a"ta\ (r[=a]"d[i^]*[=a]"t[.a]), n. pl. [NL., fr.
   radiatus, p. p. See Radiate.] (Zool.)
   An extensive artificial group of invertebrates, having all
   the parts arranged radially around the vertical axis of the
   body, and the various organs repeated symmetrically in each
   ray or spheromere.
   [1913 Webster]

   Note: It includes the c[oe]lenterates and the echinoderms.
         Formerly, the group was supposed to be a natural one,
         and was considered one of the grand divisions of the
         animal kingdom.
         [1913 Webster]