The caudal fin, also known as the tail fin, is an essential feature of fish anatomy that helps them move forward and change direction. There are many synonyms for the term "caudal fin," which includes tail, fluke, and tail fin. The tail is the most basic term that refers to the rear part of a fish's body which also contains the tail fin. Fluke, on the other hand, is used to describe the broad, paddle-like tail of some fish species. The tail fin, on the other hand, is more specific and refers specifically to the fins found at the end of the fish's body. Overall, these synonyms provide variety and offer greater precision in describing the intricacies of fish anatomy.