dorsal fin

noun

1. the fin or finlike integumentary expansion generally developed on the back of aquatic vertebrates.

dorsal fin

noun

1. any unpaired median fin on the backs of fishes and some other aquatic vertebrates: maintains balance during locomotion

Word History and Origins

Origin of dorsal fin¹

First recorded in 1760–70

Example Sentences

It has silvery blue skin and a red dorsal fin that runs the length of its body.

From The Daily Beast

A dorsal fin cut the surface close by, there was a little flurry, and the pirate disappeared.

From Project Gutenberg

The back, dorsal fin and tail are generally well covered with dark brownish black spots.

From Project Gutenberg

Dorsal fin double, the first half having ten spines and the latter twenty-one or twenty-two soft rays.

From Project Gutenberg

The unpaired dorsal fin develops as a continuous thickening, which then grows up into a projecting fold of columnar cells.

From Project Gutenberg

The dorsal fin runs along the whole length of the back, and each pelvic has one spine and two soft rays.

From Project Gutenberg