Definition of fin in English:

fin

Line breaks: fin
Pronunciation: /fɪn
 
/

noun

1A flattened appendage on various parts of the body of many aquatic vertebrates, including fish and cetaceans, and some invertebrates, used for propelling, steering, and balancing.
More example sentences
  • He then uses this to explain why there are no post-anal fins in fish: the tail is itself an appendage.
  • Powerful fins propel the streamlined fish toward meals of smaller fish and squid - and away from hungry sharks.
  • In essence, only the paired fins and the tail fin remain.
1.1An underwater swimmer’s flipper.
More example sentences
  • Training equipment such as kickboards, pull buoys, and fins help all swimmers to isolate or emphasize certain movements.
  • The next steps involve the whole stroke, removing the fins, underwater kicking to stroke start and finally the block start.
  • You take a look around the pool and are surprised to see that a number of swimmers are using fins, especially on kick sets.
1.2A small flattened projecting surface or attachment on an aircraft, rocket, or car, for providing aerodynamic stability.
More example sentences
  • The center fin was a fixed surface, extending vertically above the stabilizer at the center line of the airplane.
  • Simply described, the fins improve directional stability by channeling and smoothing the airflow around the tailcone.
  • Aerodynamic fins located on the aft bay of the strap-ons also provided for flight control.
1.3A flattened projection on a device, used for increasing heat transfer.
More example sentences
  • The fins conduct heat from the tubes and then transfer it to the air flowing through the radiator.
  • Concrete structural fins act as shading devices on the north-south axis.
  • The top and bottom of the Cool Drive have fins for heat dissipation.

verb (fins, finning, finned)

[no object, with adverbial of direction] Back to top  
Swim under water by means of flippers: we finned along the side of the wreck
More example sentences
  • They then did some shallow water running followed by duck diving and finning (swimming with flippers).
  • I finned along the starboard side to the base of the bow, where I found a monster edible crab.
  • We finned back along the port side and, after a bottom time of 15 minutes, our slow ascent up the shotline commenced.

Origin

Old English finn, fin, of Germanic origin; related to Dutch vin and probably ultimately to Latin pinna 'feather, wing'.

Derivatives

finless

adjective
More example sentences
  • Researchers in inspection stations will closely watch the white-flag dolphins and finless porpoises.
  • These butchered, finless, and fully conscious creatures, sink to the bottom.
  • Below the iconic duo a trio of very sorry looking, finless, sharks are shown floundering.

finned

adjective
[in combination]: long-finned pike

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