1. Aeron.the ratio of the span of an airfoil to its mean chord.
2. Television.the ratio of the width of an image to its height, usually the ratio 4 to 3.
3. Naval Archit.the ratio of the height of a rudder to its fore-and-aft length.
4. Rocketry. a. Also called fineness ratio, slenderness ratio. the ratio of the mean diameter of the body of a rocket or missile to its length.
b. the ratio of the length of the combustion chamber of a rocket motor to its diameter.