The Chinese word 密封 (mìfēng), meaning "to seal airtight" or "hermetic", is a compound formed by combining two meaningful characters: 密 (mì), which conveys ideas of density, tightness, closeness, and secrecy; and 封 (fēng), which means to seal, to close, or to confer. Together, they create a coordinative or complementary compound where the first character describes the manner ("tightly/densely") and the second specifies the action ("to seal"). Thus, the term literally and conceptually signifies the act of "closing something tightly" to prevent the passage of air or liquid, effectively capturing its modern technical meaning.