magnetic variationmagnetic variation
- Differences in the earth's magnetic field in time and location.
- See magnetic declination.
(plural magnetic variations)
- (military, nautical, navigation) In navigation, at a given place and time, the horizontal angle between the true north and magnetic north measured east or west according to whether magnetic north lies east or west of true north.
- (cartography) In cartography, the annual change in direction of the horizontal component of the Earth's magnetic field.