dorsal fin

American  

noun

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

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dorsal fin British  

noun

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

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Etymology

Origin of dorsal fin

First recorded in 1760–70

Example Sentences

Dorsal fin like that of Atlantic bottlenosed dolphin; located near midpoint of back.

From Whales, Dolphins, and Porpoises of the Western North Atlantic A Guide to Their Identification by Caldwell, David

Dorsal fin nearly as long as the body, with simple flexible rays.

From Zoological Illustrations, Volume I or Original Figures and Descriptions of New, Rare, or Interesting Animals by Swainson, William

Dorsal fin falcate and distinct, in last one-third of back.

From Whales, Dolphins, and Porpoises of the Western North Atlantic A Guide to Their Identification by Caldwell, David

Dorsal fin moderately falcate to triangular and very erect.

From Whales, Dolphins, and Porpoises of the Western North Atlantic A Guide to Their Identification by Caldwell, David

Dorsal fin broad-based, falcate to flaglike, in front half of back.

From Whales, Dolphins, and Porpoises of the Western North Atlantic A Guide to Their Identification by Caldwell, David