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1. The cardinal number that is the sum of four and one
   - five, 5, V, cinque, quint, quintet, fivesome, quintuplet, pentad, Phoebe, Little Phoebe
    
2. One of a pair of decorations projecting above the rear fenders of an automobile
   - tail fin, tailfin
    
3. One of a set of parallel slats in a door or window to admit air and reject rain
   - louver, louvre
    
4. A shoe for swimming; the paddle-like front is an aid in swimming (especially underwater)
   - flipper
    
5. A stabilizer on a ship that resembles the fin of a fish
    
6. Organ of locomotion and balance in fishes and some other aquatic animals

1. Equip (a car) with fins
    
2. Propel oneself through the water in a finning motion
    
3. Show the fins above the water while swimming
   "The sharks were finning near the surface"
   - break water

Sounds like: Finn

Derived forms: finned, finning, fins

Type of: appendage, decoration, digit, equip, extremity, figure, fit, fit out, member, ornament, ornamentation, outfit, shoe, slat, spline, stabiliser [Brit], stabilizer, swim

Part of: auto, automobile, car, fish, jalousie, machine, motorcar, ship

Encyclopedia: Fin