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

We strongly suspected that these never-before-seen bones hidden in the pectoral fin of this ancient fish were actually digit bones similar to the ones found in the fingers of tetrapods.

From Scientific American • Jun. 17, 2020

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