The diver put on fins before entering the sea.
fin (of a surfboard, aircraft, etc.)
Refers to stabilizing or steering fins on equipment such as surfboards, boats, or aircraft.
The fin of the surfboard broke.
He attached a fin to the surfboard to improve stability.
He can swim quickly using fins.
pair; couple; matched set · antithesis; parallel contrast · counter for pairs · counter for sets; counter for matched utensils or furnishings
monofin
tail fin
fin swimming; finswimming
fin stabilizer
Borrowed from English 'fin'.