Light

noun

1. Visible electromagnetic radiation. The human eye can typically detect radiation (light) in the wavelength range of about 400 to 750 nanometers. Nearby shorter and longer wavelength ranges, although not visible, are commonly called ultraviolet and infrared light.

   "As you can see, this spacious dining-room gets a lot of light in the mornings."

2. A source of illumination.

   "Put that light out!"

3. Spiritual or mental illumination; enlightenment, useful information.

   "Can you throw any light on this problem?"

4. (in the plural) Facts; pieces of information; ideas, concepts.
5. A notable person within a specific field or discipline.

   "Picasso was one of the leading lights of the cubist movement."