/ray'dee ay"teuh, -ah"teuh/ , n. Biol.
(in some classification systems) a major grouping that includes more or less radially symmetrical animals, as coelenterates (jellyfish, sea anemones, corals), ctenophores (comb jellies), and echinoderms (starfish, sea urchins, sea cucumbers).
[ 1820-30; radiatus RADIATE (adj.) ]