1. a white ceremonial ensign with a royal cipher, flown on special occasions by the British Royal Navy.
2. the union jack as an emblem on the regimental colors of a British military unit.
3. king's colors, a pair of silk flags with the British royal cipher, announcing the monarch's presence. Also called, when a queen is sovereign, queen's color.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.