axis

n. 轴

Does the earth rotate on an axis?

地球是绕轴旋转的吗？

In computer graphics, turning all or part of a display image180 degrees about an axis in the plane of the display surface.

在计算机制图技术中，显示图象的全部或一部分对显示面所在平面中某个轴线翻转180度的处理方法。