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

See Examples For:

dorsal fin

Winter had put a life vest on the dog resembling a shark, with a dorsal fin protruding from its back.

From Los Angeles Times ● Oct. 9, 2024

The dorsal fin is like a dolphin's fingerprint, as each has distinctive notches, ridges and pigmentation.

From BBC ● Aug. 26, 2024

What they spotted, a whale without a dorsal fin, led the researchers to think that it might be a North Atlantic right whale, a critically endangered species that the aquarium has been closely monitoring.

From New York Times ● Mar. 6, 2024

They can be identified by their lack of a dorsal fin and mottled appearance that makes them very different from whales more commonly seen off New England such as the humpback whale and minke whale.

From Seattle Times ● Mar. 5, 2024

Her dog growled, the hair on its back standing straight up like a dorsal fin.

From "Blood of Olympus" by Rick Riordan