Sagitta /(?)/

Sa·git·ta

Sagitta

n.
  1. A small constellation north of Aquila; the Arrow. (Astron.)
  2. The keystone of an arch. (Arch.) [R.]
  3. The distance from a point in a curve to the chord; also, the versed sine of an arc; -- so called from its resemblance to an arrow resting on the bow and string. (Geom.) [Obs.]
  4. The larger of the two otoliths, or ear bones, found in most fishes. (Anat.)
  5. A genus of transparent, free-swimming marine worms having lateral and caudal fins, and capable of swimming rapidly. It is the type of the class Chaetognatha. (Zool.)