The Chinese word "生日" (shēngrì) is formed by combining two individual characters: "生", which conveys the concept of birth or life, and "日", which means day. Together, they create a compound meaning that directly translates to "birth day", where the first character denotes the event of being born and the second specifies the temporal unit, thus collectively representing the day on which a person is born. This formation follows a straightforward semantic composition where the meanings of the constituent characters are merged to express a new, related idea.