magnetic north 
noun
The direction in which the north end of a compass needle or other freely suspended magnet will point in response to the earth’s magnetic field. It deviates from true north over time and from place to place because the earth’s magnetic poles are not fixed in relation to its axis.There had been hopes that the variation of the compass - the angle between the directions of magnetic north and true north - might do the trick, since it was known to vary with position on the earth....
- The compass needle and a knowledge of magnetic declination, the angle between the magnetic north and geographic north, were developments from this knowledge; they were described by Shen Kua in 1088.
- During his expeditions in the Americas and Europe, he recorded and reported on magnetic declination - the angle between magnetic north and true north at a particular location.
- double bond
- double-book
- double-breasted
- double bridle
- double-check
- double chin
- double-chinned
- double-click
- double-clutch
- double coconut
- double concerto
- double convict
- double cream
- double-cross
- double-crosser
- double-cut
- double-cut roll
- double dagger
- double date
- Doubleday, Abner
- double-dealer
- double-dealing
- double-decker
- double-declutch
- double decomposition