Définitions
1.NounA window, dome, or opening in the roof or ceiling, to admit natural light.
2.NounDiffuse sky radiation—solar radiation reaching the earth's surface after having been scattered from the direct solar beam by molecules or suspensoids in the atmosphere.
3.NounA hole in the upper part of a lava tube, yielding a view of the lava within.
4.NounA region of flat, thin ice allowing a submarine to surface.