An organ attached to various parts of the body in fishes and cetaceans, which serves for propelling and steering in the water. With prefixed…

attributive. Of or pertaining to the back, used for or carried on the back, e.g. back-ache, back-cloth, back-clout, back-fin; back-basket, back-burden…

Anatomy and Zoology. Of, pertaining to, situated in or on, the abdomen; abdominal. In ventral fin. (Cf. B. 1.)

Zoology. Short for pectoral fin n. at compounds.

A ventral fin; one of the fins corresponding to the hind legs of quadrupeds.

Chiefly Zoology. A subdorsal part, appendage, or marking.

Any of various structures in vertebrates functioning as fins, wings, or feathers; esp. a fin of a fish; a flipper of a seal or whale. Obsolete.