The spectrum of the Sun peaks in the 'yellow' region and falls away towards the red and blue parts of the visible spectrum. This gives sunlight, to the human eye, a yellowish color. White light is produced by combining the full spectrum so that each color is represented with the same intensity. In the case of sunlight used in a prism, 'white' is meant to indicate more the combination of all colors into a single continuum, than to express its actual color.