The combination of these four characters—`兄`+`弟`+`姐`+`妹`—literally covers every possible sibling relationship, creating the complete and collective term 兄弟姐妹.
The term 兄弟姐妹 is a window into traditional Chinese family values, which are heavily influenced by Confucianism. The key takeaway is the emphasis on hierarchy and specific roles. In Western culture, “siblings” is a neutral, flat term. We must add adjectives like “older” or “younger” to specify. In Chinese, this distinction is embedded in the core nouns: `哥哥 (gēge)`, `弟弟 (dìdi)`, `姐姐 (jiějie)`, and `妹妹 (mèimei)`. The term 兄弟姐妹 is simply the collection of these distinct roles. This structure reflects a cultural value system where age dictates respect and responsibility. An older sibling, especially a `哥哥 (gēge)`, was traditionally expected to protect, guide, and even provide for their younger siblings. In return, younger siblings were expected to show respect, listen to, and learn from their elders. This concept has been profoundly impacted by China's One-Child Policy (approx. 1980-2015). For a generation of `独生子女 (dúshēng zǐnǚ)` or “only children,” the direct experience of having 兄弟姐妹 was rare. For them, cousins (`堂兄弟姐妹` or `表兄弟姐妹`) often filled a similar social and emotional role.
While its cultural roots are deep, the term's practical usage is straightforward but with important distinctions.