Akademik

(physics) the angle that a magnetic needle makes with the plane of the horizon

dip¹ (def. 32).

angle of dip,

1. the angle of downward inclination from the horizontal of the needle of a magnetic compass, ranging from 0 degrees at the magnetic equator to 90 degrees at either of the magnetic poles.

2. Geology. the angle of downward inclination from the horizontal in a plane of stratification.