tail fin Syllabification: (tail fin)Definition of tail fin noun Zoology a fin at the posterior extremity of a fish’s body, typically continuous with the tail. Also called caudal fin. Aeronautics a projecting vertical surface on the tail of an aircraft, providing stability and typically housing the rudder. an upswept projection on each rear corner of an automobile, popular in the 1950s. tail fin in other Oxford dictionaries Definition of tail fin in the British & World English dictionary
