With respect to, or concerning the side in which the backbone is located, or the analogous side of an invertebrate. (wikipedia.org)
2. Refers to anatomical structures that are either situated toward or grow off that side of an animal. The opposite side of the animal is described with the terms ventrum and ventral. (wikipedia.org)
3. Of, on, or relating to the upper side or back of an animal, plant, or organ. (Google Dictionary)
4. Belonging to or on or near the back or upper surface of an animal or organ or part. (wordnetweb.princeton.edu)
Facing away from the axis of an organ or organism. (wordnetweb.princeton.edu)
Of, or pertaining to, the dorsum. (biology-online.org)
Word origin: From Latin dorsum ‘back’ or dorsālis (“of or relating to the back”).