declination

The ship's navigator calculated the magnetic declination to ensure they stayed on the correct course.

(Chinese) 船只导航员计算了磁偏角，以确保他们保持在正确的航线上。

Historians observed a steady declination in the influence of the old empire over its neighbors.

(Chinese) 历史学家观察到旧帝国对其邻国的影响力在稳步下降。