The term 大姐 (dàjiě) is a compound word formed by combining the adjective 大 (dà), meaning "big" or "oldest", with the noun 姐 (jiě), meaning "older sister". It follows a common modifier-head structure in Chinese, where the first element specifies a characteristic of the second. Literally translating to "biggest sister", it primarily refers to one's eldest sister within a family hierarchy. Beyond the immediate family, it is also widely used as a polite and respectful form of address for an unrelated woman who is roughly one's senior, functioning similarly to "miss" or "ma'am" in English, but with a familiar and affectionate tone that acknowledges both age and social respect.