natural light
General term for light from the sun or other natural sources, as opposed to artificial light (人工光).
See also: 人工光
This room is bright because it gets a lot of natural light.
unpolarized light
Physics term for light whose electric field vibrates in all directions perpendicular to the direction of propagation.
Natural light becomes polarized when it passes through a polarizing filter.
Compound of 自然 (natural) and 光 (light).