Definition that contains chaetognath
- worm any of numerous relatively small elongated soft-bodied animals especially of the phyla Annelida and Chaetognatha and Nematoda and Nemertea and Platyhelminthes; also many insect larvae
- genus sagitta chief genus of Chaetognatha including the largest arrowworms
- arrowworm 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
- chaetognath 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