When combined, 直系亲属 (zhíxì qīnshǔ) literally translates to “straight-line-connection-kin-category,” perfectly capturing the concept of relatives in a direct, vertical lineage.
The concept of `直系亲属` is deeply rooted in Confucian values that have shaped Chinese society for millennia. The emphasis is on a clear, hierarchical family structure and the concept of 孝顺 (xiàoshùn), or filial piety. This vertical line represents the flow of life, respect, and responsibility.
In contrast, the common Western idea of “immediate family” is often more horizontal and nuclear, typically centered around the couple and their children, and very frequently including siblings. The Chinese term `直系亲属` is stricter and more focused on the bloodline of ancestry and descent. A sibling, while extremely close, is considered 旁系亲属 (pángxì qīnshǔ), or a “collateral/side-line relative,” as they branch off from the parents rather than continuing the direct vertical line from you. This distinction is crucial in legal and traditional contexts.
You will almost never hear `直系亲属` used in casual, everyday conversation. It is a formal, technical term primarily found in written documents and official settings.
The connotation is entirely neutral and formal. Using it in a casual setting to introduce your parents would sound very strange and emotionally distant, like calling them “my lineal ascendants.”