\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.