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 part gray, part black; tall and distinctly falcate.

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

Dorsal fin located near midpoint of back; head longGo to 28 27. a.

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, thirty-one; anterior very strong, first short.

From Narrative of a Survey of the Intertropical and Western Coasts of Australia Performed between the years 1818 and 1822 — Volume 2 by King, Phillip Parker