The word "锈斑" is formed by combining the character "锈", meaning rust, which consists of the metal radical "钅" indicating its relation to metal and the phonetic component "秀" suggesting its pronunciation, with the character "斑", meaning spot or stain, composed of the radical "文" hinting at pattern and the component "玨" implying something marked or speckled. Together, they create a compound word where "锈" conveys the substance and "斑" denotes the appearance, resulting in the meaning of a rust spot or stain.