declination/ˌdeklɪˈneɪʃn; ˌdɛklə`neʃən/ n[U, C](physics 物) deviation of the needle of a compass, east or west from true north （罗盘指针的）偏差（如正北偏东或偏西）; 磁偏角.
牛津英汉双解词典