Definition that contains magnetic declination
- isogone an imaginary line connecting points on the Earth's surface where the magnetic declination is the same
- isogonal line an imaginary line connecting points on the Earth's surface where the magnetic declination is the same
- agonic line an imaginary line connecting points on the Earth's surface where the magnetic declination is zero
- isogonic line an imaginary line connecting points on the Earth's surface where the magnetic declination is the same
- declinometer an instrument for measuring magnetic declination
- transit declinometer an instrument for measuring magnetic declination