ABSTRACT
Light outdoors is generally referred to as natural light. It has two main components: that arriving directly from the sun is referred to as sunlight ( or ‘beam sunlight ’ ). Varying fractions of this are diffused by the atmosphere, e.g. by clouds, which is referred to as daylight. (Some authors refer to the latter as ‘ skylight ’, but in general usage, also adopted here, skylight means a roof window.)
The term daylight, in a loose sense is often used for both, but in technical language (also used here) it means only the diffused light arriving from the sky hemisphere.
