caudal fin

noun

the terminal vertical fin of a fish.

Also called tail fin.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for caudal fin

caudal fin

noun

the tail fin of fishes and some other aquatic vertebrates, used for propulsion during locomotion

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012