Agonic line

An irregular imaginary line across the surface of the Earth along which the magnetic and geographic poles are in alignment, and along which there is no magnetic variation.

Source: Pilot's Handbook of Aeronautical Knowledge (definition from the FAA-H-8083-25B, 2016; current: FAA-H-8083-25C, 2023, with the October 2025 addendum).

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Glossary last updated 2026-10-28.

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