fin

Short definition from Wiktionary

Noun

1. 1
   One of the appendages of a fish, used to propel itself and to manoeuvre/maneuver.
2. 2
   A similar appendage of a cetacean or other marine animal.
3. 3
   A thin, rigid component of an aircraft, extending from the fuselage and used to stabilise and steer the aircraft.
4. 4
   A similar structure protruding from a projectile, used to help keep it on course.
5. 5
   A similar structure on the bottom of a surfboard, used to help steer it.
6. 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. 7
   A device worn by divers and swimmers on their feet.
8. 8
   An extending part on a surface of a radiator, engine, heatsink, etc., used to facilitate cooling.
9. 9
   A sharp raised edge (generally in concrete) capable of damaging a roof membrane or vapor retarder.
10. 10
    The conning tower of a submarine.
11. 11
    A person's hand.
12. 12
    a five-pound (£5) note; the sum of five pounds.
13. 13
    A five-dollar bill; the sum of five dollars.
14. 14
    "The end".
15. 15
    Denotes the end of the road.
16. 16
    Initialism of facility ID number.
17. 17
    Initialism of force identification number.

Verb

1. 1
   To cut the fins from a fish, shark, etc.
2. 2
   (Of a fish) to swim with the dorsal fin above the surface of the water.
3. 3
   To swim in the manner of a fish.
4. 4
   To provide (a motor vehicle etc) with fins.

Proper noun

1. 1
   commune in the Somme department in France