tail fin
  尾鰭
  tail fin
       n 1: a stabilizer that is part of the vertical tail structure of
            an airplane [syn: vertical stabilizer, vertical
            stabiliser, vertical fin, tailfin]
       2: one of a pair of decorations projecting above the rear
          fenders of an automobile [syn: tailfin, fin]
       3: the tail of fishes and some other aquatic vertebrates [syn:
          caudal fin]