tail fin
noun
1- Zoology a fin at the posterior extremity of a fish's body, typically continuous with the tail【动】（鱼的）尾鳍。亦称CAUDAL FIN.
1.1
- Aeronautics a projecting vertical surface on the tail of an aircraft, providing stability and typically housing the rudder【航空】（端板式）垂直尾翼。
1.2
- an upswept projection on each rear corner of a motor car, popular in the 1950s（20世纪50年代流行的）汽车尾翼。