A flattened appendage on various parts of the body of many aquatic vertebrates and some invertebrates, used for propelling, steering, and balancing. The shark's dorsal fin sliced through the water as it approached the boat.
A thin, flat part that sticks out from an object and is used to improve its movement through air or water. The rocket's fins help stabilize it during flight.
A slang term for a five-dollar bill in the United States. He handed the cashier a fin to pay for his coffee.
The word “fin” used on screen or in print to mark the end of a film, book, or story. The silent film faded to black and the single word "fin" appeared.