The term 'royal color' can refer to two colors: PURPLE and BLUE. PURPLE is a color that has been associated with royalty since ancient times, and is often used to represent wealth and power. BLUE, on the other hand, is a color that has been associated with the sky and sea, and is often used to represent loyalty and trustworthiness. Both colors are commonly used in royal regalia and flags, and have become symbols of royalty throughout the world.