Plain English Meaning

The direction your nose is pointing, measured against magnetic north rather than the geographic North Pole.

Full Definition

The direction the airplane's nose is pointing, measured in degrees clockwise from magnetic north. It is true heading corrected for magnetic variation but not yet corrected for compass deviation.

Context Anchor

Used during straight flight, navigation, and heading control when a pilot holds or turns to a compass-based direction.

Derivation

Magnetic' refers to Earth's magnetic field, which is what a compass actually senses. Magnetic north and the geographic (true) are not in the same place, so a heading based on the magnetic field will differ from one based on the true pole.