The Chinese word 兄妹 is a compound noun formed by combining two individual characters: 兄 (xiōng), meaning "older brother", and 妹 (mèi), meaning "younger sister". This is a common coordinative structure in Chinese where two semantically related terms are joined to create a new, broader concept. The word does not follow a "subject-verb" or "modifier-head" logic but instead presents the two elements as a paired set, collectively meaning "brother and sister" with an implied order of an elder brother and a younger sister, thus specifying both the sibling relationship and the relative ages and genders.