declination; angle of deviation
General term for an angular deviation from a reference direction, used in navigation, astronomy, and engineering.
argument (of a complex number)
Mathematical term for the angle between the positive real axis and the line from the origin to a complex number in the complex plane.
It is necessary to take into account the declination between magnetic north and true north.
The argument of a complex number represents the angle from the origin.
isogonic line; isogonal line
Compound of 偏 (へん, 'deviation, inclination') and 角 (かく, 'angle'). The term is used in technical fields to denote an angular deviation.