Source : Webster's Revised Unabridged Dictionary (1913)

Annelida \An*nel"i*da\, n. pl. [NL. See {Annelid}.] (Zo["o]l.)
   A division of the Articulata, having the body formed of
   numerous rings or annular segments, and without jointed legs.
   The principal subdivisions are the {Ch[ae]topoda}, including
   the {Oligoch[ae]ta} or earthworms and {Polych[ae]ta} or
   marine worms; and the {Hirudinea} or leeches. See
   {Ch[ae]topoda}.

Annulata \An`nu*la"ta\, n. pl. [Neut. pl., fr. L. annulatus
   ringed.] (Zo["o]l.)
   A class of articulate animals, nearly equivalent to
   {Annelida}, including the marine annelids, earthworms,
   Gephyrea, Gymnotoma, leeches, etc. See {Annelida}.

Source : WordNet®

Annelida
     n : segmented worms: earthworms; lugworms; leeches [syn: {phylum
         Annelida}]