fin

a membranous, winglike or paddlelike organ attached to any of various parts of the body of fishes and certain other aquatic animals, used for propulsion, steering, or balancing.

Nautical.

1. a horizontal, often adjustable, winglike appendage to the underwater portion of a hull, as one for controlling the dive of a submarine or for damping the roll of a surface vessel.

2. fin keel.

Also called vertical stabilizer.  Aeronautics. any of certain small, subsidiary structures on an aircraft, designed to increase directional stability.

any of a number of standing ridges on an ordinarily hot object, as a radiator, a cylinder of an internal-combustion engine, etc., intended to maximize heat transfer to the surrounding air by exposing a large surface area.

any part, as of a mechanism, resembling a fin.

Metallurgy. a ridge of metal squeezed through the opening between two rolls, dies, or halves of a mold in which a piece is being formed under pressure.

Automotive. an ornamental structure resembling an aeronautical fin that is attached to the body of an automobile, as on each rear fender tail fin.

Slang. the arm or hand.

Usually fins. flipper.

to cut off the fins from (a fish); carve or cut up, as a chub.

to provide or equip with a fin or fins.

any of the firm appendages that are the organs of locomotion and balance in fishes and some other aquatic animals. Most fishes have paired and unpaired fins, the former corresponding to the limbs of higher vertebrates

a part or appendage that resembles a fin

1. US name: vertical stabilizer.  a vertical surface to which the rudder is attached, usually placed at the rear of an aeroplane to give stability about the vertical axis

2. a tail surface fixed to a rocket or missile to give stability

nautical a fixed or adjustable blade projecting under water from the hull of a vessel to give it stability or control

a projecting rib to dissipate heat from the surface of an engine cylinder, motor casing, or radiator

(often plural) another name for flipper