Airfoil and Dorsal fin

Airfoil noun - A device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight.

Dorsal fin and airfoil are semantically related. In some cases you can use "Dorsal fin" instead a noun "Airfoil".

Dorsal fin noun - Unpaired median fin on the backs of fishes and some other aquatic vertebrates that help to maintain balance.

Airfoil and dorsal fin are semantically related. You can use "Airfoil" instead a noun phrase "Dorsal fin".