Source : Webster's Revised Unabridged Dictionary (1913)

Backband \Back"band`\ (-b[a^]nd), n. [2nd back, n. + band.]
   (Saddlery)
   The band which passes over the back of a horse and holds up
   the shafts of a carriage.

Source : WordNet®

backband
     n : a broad band that passes over the back of a horse and
         supports the shafts of a vehicle