noun the harp seal.
2. saddleback ·adj ·same·as saddle-backed.
3. saddleback ·noun the great blackbacked gull (larus marinus).
4. saddleback ·noun anything saddle-backed; ·esp., a hill or ridge having a concave outline at the top.
5. saddleback ·noun the larva of a bombycid moth (empretia stimulea) which has a large, bright green, saddle-shaped patch of color on the back.