Source : Webster's Revised Unabridged Dictionary (1913)

Saddleback \Sad"dle*back`\, a.
   Same as {Saddle-backed}.

   {Saddleback roof}. (Arch.) See {Saddle roof}, under {Saddle}.

Saddleback \Sad"dle*back`\, n.
   1. Anything saddle-backed; esp., a hill or ridge having a
      concave outline at the top.

   2. (Zo["o]l.)
      (a) The harp seal.
      (b) The great blackbacked gull ({Larus marinus}).
      (c) The larva of a bombycid moth ({Empretia stimulea})
          which has a large, bright green, saddle-shaped patch
          of color on the back.

Source : WordNet®

saddleback
     n 1: a pass or ridge that slopes gently between two peaks (is
          shaped like a saddle) [syn: {saddle}]
     2: a double sloping roof with a ridge and gables at each end
        [syn: {gable roof}, {saddle roof}, {saddleback roof}]