dorsal fin
noun
plural dorsal fins
: a flat thin body part that projects from the back of many fish (such as trout, barracuda, and sharks) and some marine mammals (such as dolphins)
Porpoises have a more triangular dorsal fin while a dolphin's dorsal fin is more curved.—
Naomi Corrigan and Dave Himelfield
Naomi Corrigan and Dave HimelfieldThis member of the perch family has two dorsal fins and a large mouth outfitted with sharp teeth …—Matt Markey
Matt MarkeyExamples of dorsal fin in a Sentence
Recent Examples on the Web
Sticking Variety Remora adhesive disks are an evolutionary adaptation of the fish’s first dorsal fin, the one that in other species sits on top of the body, just behind the head and gill covers.
—Jacek Krywko, ArsTechnica, 9 Aug. 2025
For a ping to register, Contender's dorsal fin must break water and an Argos satellite must be nearby to record the shark's location.
—Stepheny Price, FOXNews.com, 23 July 2025
The caseback is engraved with the image of the Orca, the boat from the film, and the shark’s dorsal fin emerging from the water.
—Carol Besler, Forbes.com, 24 June 2025
Spines hold the dorsal fin up from the fish’s back, starting with longer spines and going to shorter spines toward the tail, with three spines on its anal fin, according to the study.
—Irene Wright, Miami Herald, 27 Jan. 2025
Groups didn’t record any feeding behavior and saw that the whale didn’t have a dorsal fin, the group said.
—Paloma Chavez, Sacbee.com, 25 July 2025
Their dorsal fins, or the top fin, are red, black and yellow.
—Olivia Lloyd, Miami Herald, 4 Apr. 2025
Erecting his sail-like, iridescent dorsal fin, the mudskipper wriggles his stout tail and launches himself into the air before falling back to earth with an unceremonious plop.
—Skylar Knight, Smithsonian Magazine, 27 June 2025
On June 27, Janet Neilson, a biologist with the Glacier Bay National Park and Preserve, saw an adult humpback whale near Willoughby Island with an injury to its dorsal fin, mostly likely from a collision with a boat, according to a July 1 news release by the National Park Service.
—Paloma Chavez
july 2, Sacbee.com, 2 July 2025
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Jacek Krywko, ArsTechnica, 9 Aug. 2025
For a ping to register, Contender's dorsal fin must break water and an Argos satellite must be nearby to record the shark's location.
—Stepheny Price, FOXNews.com, 23 July 2025
The caseback is engraved with the image of the Orca, the boat from the film, and the shark’s dorsal fin emerging from the water.
—Carol Besler, Forbes.com, 24 June 2025
Spines hold the dorsal fin up from the fish’s back, starting with longer spines and going to shorter spines toward the tail, with three spines on its anal fin, according to the study.
—Irene Wright, Miami Herald, 27 Jan. 2025
Groups didn’t record any feeding behavior and saw that the whale didn’t have a dorsal fin, the group said.
—Paloma Chavez, Sacbee.com, 25 July 2025
Their dorsal fins, or the top fin, are red, black and yellow.
—Olivia Lloyd, Miami Herald, 4 Apr. 2025
Erecting his sail-like, iridescent dorsal fin, the mudskipper wriggles his stout tail and launches himself into the air before falling back to earth with an unceremonious plop.
—Skylar Knight, Smithsonian Magazine, 27 June 2025
On June 27, Janet Neilson, a biologist with the Glacier Bay National Park and Preserve, saw an adult humpback whale near Willoughby Island with an injury to its dorsal fin, mostly likely from a collision with a boat, according to a July 1 news release by the National Park Service.
—Paloma Chavez
july 2, Sacbee.com, 2 July 2025
Cite this Entry
“Dorsal fin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/dorsal%20fin. Accessed 1 Sep. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share