white light

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Electromagnetic radiation of all the frequencies in the visible range of the spectrum, appearing white to the eye.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun uncountable Light, having a mixture of frequencies, being perceived as having no specific colour; such as sunlight.
• noun countable A white-coloured light or lamp