The word 封面 is formed by combining two meaningful components: 封, which carries the core idea of "to seal" or "to cover", and 面, which means "surface" or "face". Together, they create a single concept through direct semantic combination, where the first element describes the function (the covering/sealing action) and the second specifies the object (the outer surface), resulting in the concrete meaning of "the front cover" of a book or magazine.