1. A stabilizer that is part of the vertical tail structure of an aeroplane
   "The tailfin helps maintain directional stability during flight";
   - vertical stabilizer, vertical stabiliser [Brit], vertical fin, tail fin
    
2. One of a pair of decorations projecting above the rear fenders of an automobile
   "The classic 1950s car was easily recognizable by its large tailfins";
   - tail fin, fin

1. The tail of fishes and some other aquatic vertebrates
   "The tuna's powerful tail fin propels it through the water at high speeds";
   - caudal fin

Derived forms: tailfins, tail fins

Type of: decoration, fin, ornament, ornamentation, stabiliser [Brit], stabilizer

Part of: auto [informal], autocar [archaic], automobile [N. Amer], car, fish, motor [Brit, informal], motorcar, vertical tail, wheel [informal], whip [US, informal]

Encyclopedia: Tailfin