On a compass rose, the difference between true north and magnetic north is referred to as what?

The difference between true north and magnetic north is referred to as variation, also known as magnetic declination. This is an important concept in navigation, as it accounts for the discrepancies between what a compass shows (magnetic north) and the geographic north pole (true north).

Variation is expressed in degrees east or west, indicating whether magnetic north is located east or west of true north. Understanding variation is crucial for accurate navigation, especially when relying on a magnetic compass, as navigators must adjust their headings to account for this difference to reach their intended destination effectively.

Other terms, such as inclination, deviation, and correction, relate to different aspects of navigation and compass use but do not specifically denote the difference between true north and magnetic north. For instance, inclination refers to the angle at which magnetic field lines enter or exit the Earth, while deviation pertains to errors caused by local magnetic influences affecting a compass. Correction can refer to adjustments made for various navigational errors, but it does not specifically address the distinction between true and magnetic north.