"Nephew" belongs to the relative title of brother-in-law, and refers to the children of sisters or younger sisters. When "uncle" is symmetrical, children who marry sisters are called nieces or nieces.
As for brothers' children, boys should be called nephews and girls should be called nieces. In modern times, nephews and children can also be children of other male relatives with the same surname. For those who are not related by blood, the eldest son of a close friend is also called a nephew in order to establish a relationship. Nephew is a social address and a polite expression.
Address for future generations
First, lineal blood relatives (lineal)
Paternal line: great-great-grandfather-great-grandfather-father (father)
Great-great-grandmother (old lady)-great-grandmother (wife)-grandmother (grandmother)-father (father)
Maternal line: great-great-grandfather-great-grandfather-mother (mother)
Great-great-grandmother (old lady)-great-grandmother (wife)-grandmother (grandmother)-mother (mother)
Son: The first son between husband and wife.
Daughter: A woman's first offspring between her husband and wife.
Sun: The second generation of husband and wife divide their grandchildren according to gender. Sometimes grandson is a neutral title.
Great-grandson: the third generation between husband and wife.
Great-great-grandson: the fourth generation between husband and wife.
Second, collateral blood relatives (collateral)
Paternal line: Bo: My father's brother, also called uncle, uncle, uncle.
Aunt: Uncle's wife.
Uncle: Father's brother, also called uncle, uncle.
Aunt: Uncle's wife.
Aunt: My father's sister, also called aunt and aunt.
Uncle: My aunt's husband.
Father's brother:
Uncle, uncle, uncle Da Die, second father, third father, brother-in-law, little father and so on. (Uncle, nephew, niece)
Uncle's wife:
Aunt, aunt, aunt, aunt, aunt, aunt, now called second mother, third mother and so on. (nephews, nieces)
Uncle's children:
Cousins have the same address as their brothers and sisters, and introduce their brothers and sisters with the word "Tang".