The Chinese word "姐姐" is formed by duplicating the character "姐", which itself is constructed from the radical "女" (depicting a woman) on the left and the component "且" on the right, with the latter historically contributing to the character's structural composition. This repetition results in a visually and structurally symmetrical word, where the identical characters are placed side by side, illustrating a common method in Chinese word formation that relies on character doubling without altering the individual components.