‖n. pl. [ NL. See Annelid. ] (Zool.) A division of the Articulata, having the body formed of numerous rings or annular segments, and without jointed legs. The principal subdivisions are the Chætopoda, including the Oligochæta or earthworms and Polychæta or marine worms; and the Hirudinea or leeches. See Chætopoda. [ 1913 Webster ]
a. (Zool.) Of the nature of an annelid. [ 1913 Webster ]
‖n. pl. [ NL.; pref. archi- + annelida. ] (Zool.) A group of Annelida remarkable for having no external segments or distinct ventral nerve ganglions. [ 1913 Webster ]