Definition of "fin" in English

noun

1. (ichthyology, zootomy) One of the appendages of a fish, used to propel itself and to manoeuvre/maneuver.

   • The fish's fins minimize water flow.

2. A similar appendage of a cetacean or other marine animal.

   • a dolphin's fin

3. A thin, rigid component of an aircraft, extending from the fuselage and used to stabilise and steer the aircraft.

   • The fin stabilises the plane in flight.

4. A similar structure protruding from a projectile, used to help keep it on course.

5. (surfing) A similar structure on the bottom of a surfboard, used to help steer it.

6. A hairstyle, resembling the fin of a fish, in which the hair is combed and set into a vertical ridge along the top of the head from about the crown to the forehead.

7. A device worn by divers and swimmers on their feet.

   • The divers wore fins to swim faster.

8. An extending part on a surface of a radiator, engine, heatsink, etc., used to facilitate cooling.

9. A sharp raised edge (generally in concrete) capable of damaging a roof membrane or vapor retarder.

10. (nautical) The conning tower of a submarine.

11. (UK, slang, obsolete) A person's hand.

verb

1. (transitive) To cut the fins from a fish, shark, etc.

2. (intransitive) (Of a fish) to swim with the dorsal fin above the surface of the water.

3. (intransitive) To swim in the manner of a fish.

   • A neutrally buoyant diver does not need to fin to maintain depth.

4. (transitive) To provide (a motor vehicle etc) with fins.

noun

1. (UK, formerly Australia, slang) a five-pound (£5) note; the sum of five pounds.

2. (US, slang, dated) A five-dollar bill; the sum of five dollars.

noun

1. (archaic, film, television) "The end".

2. (obsolete, road signs) Denotes the end of the road.