Runway

According to the International Civil Aviation Organization (ICAO) a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt, concrete, or a mixture of both) or a natural surface (grass, dirt, gravel, ice, or salt). ... Runways are named by a number between 01 and 36, which is generally one tenth of the magnetic azimuth of the runway's heading in degrees: a runway numbered 09 points east (90°), runway 18 is south (180°), runway 27 points west (270°) and runway 36 points to the north (360° rather than 0°). When taking off from or landing on runway 09, a plane would be heading 90° (east). However, runways in North America that lie within the Northern Domestic Airspace of Canada are numbered relative to true north because proximity to the magnetic North Pole makes the magnetic declination large. [Runway. Wikipedia]