Source : Webster's Revised Unabridged Dictionary (1913)

Boomerang \Boom"er*ang\, n.
   A very singular missile weapon used by the natives of
   Australia and in some parts of India. It is usually a curved
   stick of hard wood, from twenty to thirty inches in length,
   from two to three inches wide, and half or three quarters of
   an inch thick. When thrown from the hand with a quick rotary
   motion, it describes very remarkable curves, according to the
   shape of the instrument and the manner of throwing it, often
   moving nearly horizontally a long distance, then curving
   upward to a considerable height, and finally taking a
   retrograde direction, so as to fall near the place from which
   it was thrown, or even far in the rear of it.

Source : WordNet®

boomerang
     n 1: a curved piece of wood; when properly thrown will return to
          thrower [syn: {throwing stick}, {throw stick}]
     2: a miscalculation that recoils on its maker [syn: {backfire}]
     v : return to the initial position from where it came; like a
         boomerang