fin /fɪn/ BrE AmE noun [countable]
[ Language: Old English ; Origin: finn ]
1 . one of the thin body parts that a fish uses to swim
2 . part of a plane that sticks up at the back and helps it to fly smoothly
3 . ( also tail fin ) a thin piece of metal that sticks out from a car or bomb at the back
4 . a ↑ flipper