pectoral fin

American  

noun

1. (in fishes) either of a pair of fins usually situated behind the head, one on each side, and corresponding to the forelimbs of higher vertebrates.

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pectoral fin British  

noun

1. either of a pair of fins, situated just behind the head in fishes, that help to control the direction of movement during locomotion

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Etymology

Origin of pectoral fin

First recorded in 1760–70

Example Sentences

“It’s using its pectoral fin as a tool,” says Chris.

From BBC • Jun. 7, 2024

But on Thursday, the whale breached for about 40 minutes, also performing several pectoral fin slaps and dives.

From Seattle Times • Nov. 30, 2023

Next, as if aware of an audience, the humpback rolled on its side and flapped a pectoral fin to splash the water.

From Washington Post • Aug. 26, 2022

In the laboratory, the scientists sliced thin pieces of bone from the lower jaws of the paddlefish and from the pectoral fin spines of the sturgeon.

From New York Times • Feb. 23, 2022

I drew a pectoral fin on the side and a pelvic fin on the bottom to help the shark move up and down.

From "The Line Tender" by Kate Allen