dorsal fin



the fin or finlike integumentary expansion generally developed on the back of aquatic vertebrates.

Origin of dorsal fin

First recorded in 1760–70 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for dorsal fin

Historical Examples of dorsal fin

  • In the figure there is represented the cross-section of a fish (its dorsal-fin D) just before the spear strikes.

    Along Alaska's Great River

    Frederick Schwatka

British Dictionary definitions for dorsal fin

dorsal fin


any unpaired median fin on the backs of fishes and some other aquatic vertebrates: maintains balance 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