A lot vs. Alot: 9 Grammatical Pitfalls
1540s, from Middle French dorsal (14c.), from Late Latin dorsalis, corresponding to Latin dorsualis "of the back," from dorsum "back," of uncertain origin.
dorsal dor·sal (dôr'səl)
Of, toward, on, in, or near the back or upper surface of an organ, a part, or an organism.
Lying on the back; supine.