fin
/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.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.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.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.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]
Swim under water by means of flippers: we finned along the side of the wreck...
- 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.
Derivatives
finless
- 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
Origin
Old English finn, fin, of Germanic origin; related to Dutch vin and probably ultimately to Latin pinna 'feather, wing'.