Uncle is the son or daughter of sister or sister, called nephew or niece.
Human reproduction is interlinked. All nationalities have a kinship appellation system to express family members. Kinship appellation refers to the name that determines the relationship between family members and themselves centered on themselves. It is the name and method of mutual appellation between relatives based on blood relatives and in laws.
It is a sign of determining the relationship between relatives and myself. The relatives of the Han nationality are well-organized and orderly: the names of the older generation include aunts, uncles, sisters and brothers, nephews and nephews, etc. The kinship of Chinese people due to in laws is quite complicated. （HanJiuJiuShiWaiShengHaiShiZhiZi）