Definition
A horizontal direction expressed in degrees measured clockwise from magnetic north, ranging from 000° to 360°. Used to describe the orientation of a runway, bearing, or course relative to the Earth's magnetic field rather than true north.
Plain English
The compass direction something points, measured in degrees from magnetic north going clockwise around to a full circle.
Context Anchor
Seen when learning how runway numbers are assigned from the direction a runway points on a compass.
Derivation
Azimuth' comes from the Arabic 'as-sumut,' meaning 'the directions.' It was adopted into navigation and astronomy to describe a horizontal angle measured around the observer. Adding 'magnetic' specifies that the angle is measured from magnetic north (where a compass points) rather than true north (the geographic pole).
Why Pilots Care
Runway numbers are taken directly from the magnetic azimuth of the runway centerline, rounded to the nearest ten degrees.
Analogy
Think of standing in the center of a compass and turning clockwise from north until you face the runway’s direction. The number of degrees you turned is the magnetic azimuth.
Intuition Check
Magnetic does not mean the runway has anything magnetic in it. It means the direction is measured from magnetic north, the north reference used by a magnetic compass.
Example Sentence 1
Runway 18 has a magnetic azimuth of approximately 180°, so an aircraft on that runway is pointing south by the compass.
Example Sentence 2
Before takeoff the pilot confirms the heading indicator matches the published magnetic azimuth of the departure runway.