dor·sal 
(dôrsəl)
(dôrsəl)adj.
1. Anatomy Of, toward, on, in, or near the back or upper surface of an organ, part, or organism.
2. Botany Of or on the surface of an organ or part facing away from the axis; abaxial.
[Middle English, from Medieval Latin dorsālis, from Latin dorsuālis, from dorsum, back.]
dorsal·ly adv.