What does "fin" mean?

1. (on a fish) a thin, flat part that sticks out from the body of a fish to help it swim and balance. 2. (swimming equipment) a long, flat rubber shoe that you wear to swim faster underwater. 3. (aerospace/mechanical) a flat part on a plane, rocket, or machine that helps it stay steady or cool down. 4. (five-pound note) a slang word for a five-pound note or five dollars. 5. (to remove fins) to cut the fins off a fish, especially a shark.

fin

n. · v.

US //ˈfɪn// UK //fˈɪn// fin

1 on a fish (n.)
A2 Elementary

a thin, flat part that sticks out from the body of a fish to help it swim and balance.

an organ of a fish or cetacean used for propulsion, steering, or balancing in water.

Example

The shark's dorsal fin appeared above the water as it swam near the boat.

Example

Marine biologists can often identify individual whales by the unique notches and scars found on their dorsal fins.
- appendage
- flipper
2 swimming equipment (n.)
B1 Intermediate Sport

a long, flat rubber shoe that you wear to swim faster underwater.

a flipper-like device worn on the feet to increase propulsion while swimming or diving.

Example

You should wear fins and a mask if you want to go snorkeling.

Example

The diver kicked his fins powerfully to reach the coral reef before the current shifted.
- flipper

Show 3 more sensesShow fewer

3 aerospace/mechanical (n.)
B2 Upper Intermediate Technical Technical

a flat part on a plane, rocket, or machine that helps it stay steady or cool down.

a fixed or adjustable vane used for aerodynamic stability or to increase the surface area for heat dissipation.

Example

The small fins on the back of the rocket help it fly straight.

Example

The engine's cooling fins were clogged with dust, causing the internal temperature to rise dangerously during the long flight.
- vane
- stabiliser
- blade
4 five-pound note (n.)
C1 Advanced Slang British English American English

a slang word for a five-pound note or five dollars.

a slang term for a five-unit currency note, specifically five pounds in the UK or five dollars in the US.

Example

He handed the shopkeeper a fin to pay for the magazine.

Example

In the old detective novel, the protagonist slipped the informant a fin in exchange for the address of the warehouse.
- fiver
5 to remove fins (v.)
C1 Advanced Technical

to cut the fins off a fish, especially a shark.

to remove the fins from a fish, often used in the context of the controversial practice of shark finning.

Example

Many countries have banned the practice of finning sharks at sea.

Example

The environmental agency reported that thousands of sharks are illegally finned every year to satisfy the demand for specialty soups.