n. 回飞镖, 飞去归来器

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.