What is the angle between true north and magnetic north referred to as?

The angle between true north and magnetic north is referred to as Magnetic Declination. This term is essential in navigation and surveying, as it represents the difference between the direction that a compass points (magnetic north) and the direction of the geographic north pole (true north). Magnetic declination varies depending on where you are on Earth and can change over time due to shifts in the Earth's magnetic field. Understanding magnetic declination is crucial for accurately orienting maps, setting up survey instruments, and ensuring correct navigation, as it allows surveyors to compensate for the variations in magnetic direction when utilizing compass readings.