Large airports have several runways. They are identified by the direction in which they point, rounding to the nearest ten degrees. So, for example, a runway identified with "36" would stand for a 360 degrees direction (i.e. North), "9" for 94 degrees, and "17" for 168 degrees. Each runway can be used in two directions, and hence has two numbers. Since the directions are necessarily opposite, the number of a runway can always be found by adding or subtracting 18 from the opposite runway number (whichever yields a positive number less than 37). For example runway 10 is called runway 28 when used in the opposite direction.
If in an airport there is more than one runway pointing in the same direction, the runways are identified by the letters L, C and R, for Left, Center and Right, behind the number. Such an example would be runways "15L", "15C" and "15R". In speech runways are always referred to by saying each digit of the number, followed by 'Left', 'Right' or 'Centre' if necessary. The first example above would be referred to as "Runway One Five Left".
For fixed wing aircraft it as advantageous to perform take-offs and landings into the wind. Airports usually have several runways, running in different directions, so that this can be done for different wind directions.
See also: Aviation
A runway can also be a stage where fashion models (sometimes called runway models) display clothing.