The Collaborative International Dictionary of English v.0.48:

chaeta \chae"ta\ (k[=e]"t[.a]), n.; pl. chaetae (k[=e]"t[=e]).
   [NL., fr. Gr. chai`th hair.] (Zool.)
   a stiff chitinous seta or bristle especially of an annelid
   worm.
   [WordNet 1.5]