White is a color, the perception of which is evoked by light that stimulates all three types of color sensitive cone cells in the human eye in nearly equal amounts and with high brightness compared to the surroundings.
White light can be generated in many ways. The sun is such a source, electric incandescence is another.
Modern light sources are fluorescent lamps and light-emitting diodes. An object whose surface reflects back most of the light it receives and does not alter its color will appear white, unless it has very high specular reflection.
Since white is the extreme end of the visual spectrum (in terms of both hue and shade), and since white objects - such as clouds, snow and flowers - appear often in nature, it has frequent symbolism.
Human culture has many references to white, often related to purity and cleanness, whilst the high contrast between white and black is often used to represent opposite extremes.
The current Icelandic word for white, hvítur, is very closely related to the Old English and Old Norse forms of the word.