white: the color white, at times intensified to a gleaming or radiant brightness
At its core this word names the color white. It covers white hair, snow, wool, ripened fields, horses, and above all the white robes worn again and again in the book of Revelation.
The word also carries an older, brighter edge. Before it settled into a plain color term it meant light or gleaming, and that brilliance surfaces at the Transfiguration, where Jesus' clothing turns a white so dazzling that, as Mark puts it, no launderer on earth could match it. Here white shades into radiant, the visible glow of heavenly glory.
In Revelation the color becomes a symbol. White clothing marks those who have been made clean and who share in Christ's victory, while the white horse, the white cloud, and the great white throne all belong to the world of divine triumph and judgment. That freight comes from how the book uses the color, not from the word itself, which stays the ordinary term for white.