Source : Webster's Revised Unabridged Dictionary (1913)

Chaetognath \Ch[ae]"tog*nath\, a. (Zo["o]l.)
   Of or pertaining to the Ch[ae]tognatha.

Source : WordNet®

chaetognath
     n : any worm of the Chaetognatha; transparent marine worm with
         horizontal lateral and caudal fins and a row of movable
         curved spines at each side of the mouth [syn: {arrowworm}]