dor·sal
adjective/ˈdɔːsl/
/ˈdɔːrsl/
[only before noun] (specialist)- on or relating to the back of a fish or an animal

enlarge image(鱼或动物)背部的,背上的,背侧的 - a shark’s dorsal fin
鲨鱼的背鳍
Word Originlate Middle English: from late Latin dorsalis, from Latin dorsum ‘back’. - a shark’s dorsal fin