orthogonal direction

例句：

1. 1.The orthogonal direction of the arrow is perpendicular to the plane it points to.
   箭头的正交方向与它指向的平面垂直。
2. 2. In the orthogonal coordinate system, the x-axis is along the positive y-axis and the z-axis is along the positive x-axis.
   在直角坐标系中，x轴沿正y轴，z轴沿正x轴。
3. 3. The orthogonal projection of a point on a plane is the line that passes through the origin and is perpendicularto the plane.
   平面上一点关于该平面的正交投影是经过原点且与平面垂直的直线。