polychæta

from The Century Dictionary.

• An order or other group of chætopodous annelids, having the body segmented, the false feet or parapodia with many ehætæ setæ or bristles (whence the name), and the head tentaculate; the polychætous worms.

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Zoöl.) One of the two principal groups of Chætopoda. It includes those that have prominent parapodia and fascicles of setæ. See Illust. under parapodia.