The word "锈蚀" is formed by combining the character "锈", meaning rust, which includes the metal radical "钅" to specify its relation to metals, with the character "蚀", meaning to corrode or erode, which incorporates the components "饣" (from "食", meaning eat) and "虫" (meaning insect) to suggest a process of gradual degradation. Together, they create a compound word that explicitly denotes the corrosion of materials, particularly through rusting.