A fin located on the backs of fish and some marine mammals.

(ichthyology) A fin, usually paired, located ventrally below the pectoral fins of a fish.

(ichthyology) A soft, fleshy fin located behind the dorsal fin and just forward of the caudal fin, found fish of certain families, believed to have some sensory function.

(ichthyology) One of a set of fins that look like horns on either side of the broad head of a manta ray.

A whale of the rorqual family (Balaenoptera physalus).

(nautical) A type of keel common in sailing yachts, its shape resembling the fin of a fish.

Alternative spelling of tailfin

Alternative spelling of finfoot

The fin of a shark, specifically the dorsal, pectoral or caudal fin. / (roofing) An upward curled felt side lap or end lap.

Describing a helicopter's shrouded tail rotor, essentially a ducted fan, intended to counteract the torque of the main rotor.