Definition of finned
: having a fin or fins
- … the real stars of underwater acoustics are the finned marine mammals, including whales, porpoises and dolphins.
- —Todd Preston
- a finned Cadillac
- a finned cylinder
- The first postwar car with fins and V-8 power set a mood of exuberance that reached its peak with the shark-finned Caddy of 1959.
- —Joseph R. Szczesny
