[1] : The Collaborative International Dictionary of English v.0.48

sagitta \sagit"ta\, n. l., an arrow.
   1. astron. a small constellation north of aquila; the
      arrow.
      1913 webster

   2. arch. the keystone of an arch. r. --gwilt.
      1913 webster

   3. geom. 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.
      obs.
      1913 webster

   4. anat. the larger of the two otoliths, or ear bones,
      found in most fishes.
      1913 webster

   5. zool. 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.
      1913 webster

[2] : WordNet (r) 2.0

sagitta
     n 1: a small constellation in the northern hemisphere between
          cygnus and aquila and crossed by the milky way
     2: any arrowworm of the genus sagitta

Sagitta >> S Words
Sagitta, definition of term: Sagitta
sagitta_pag1.html