Source : Webster's Revised Unabridged Dictionary (1913)

Radiata \Ra`di*a"ta\, n. pl. [NL., fr. radiatus, p. p. See
   {Radiate}.] (Zo["o]l.)
   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.

   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.