What does the term 'magnetic variation' refer to?

The term 'magnetic variation' specifically refers to the difference between magnetic north and true north. This difference arises because the Earth's magnetic field is not perfectly aligned with the geographic poles. Magnetic north is where a magnetic compass points, while true north is the direction along the Earth's surface towards the North Pole.

Understanding magnetic variation is crucial for navigation, as it affects how pilots and navigators interpret compass readings to ensure accurate course plotting. By knowing the magnetic variation at a given location, aviators can adjust their headings accordingly.

Other potential answers pertain to concepts that are distinct from magnetic variation. For instance, deviation from aircraft materials relates to magnetic interference rather than the general concept of variation between magnetic and true north. The calculation method for navigation involves more complex procedures and tools that might take magnetic variation into account, but it is not the definition of the term itself. Lastly, the range of magnetic frequencies is unrelated to magnetic variation, as this focuses on different aspects of magnetism rather than navigational direction.