noun
1. : a ray in a symmetrical optical system that is neither parallel to nor intersecting the axis
2. : a ray of a prism not perpendicular to the edge
noun
1. : a ray in a symmetrical optical system that is neither parallel to nor intersecting the axis
2. : a ray of a prism not perpendicular to the edge
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012