The word 除了 is formed by combining the character 除, which carries the core meaning of "to remove" or "to exclude", with the character 了, which here functions not as a tense marker but as a grammatical particle that completes and substantiates the action, giving it a sense of settled or defined exception. This fusion creates a single conceptual unit that conveys the idea of "setting something aside" or "making an exclusion", forming the basis for its functional meaning of "except for" or "in addition to".