Pick any two perpendicular directions Then the same entity, the same arrow which has an existence of its own, independent of axis, can be described by you and me using different numbers.

选取两个互相垂直的方向,这样同样的物体,同一矢量,并且是独立于坐标轴而存在的,可以被你和我用不同的数字来描述

耶鲁公开课 - 基础物理课程节选

They are orthogonal.

他们是互相垂直的。

麻省理工公开课 - 固态化学导论课程节选