People who are unrelated to each other meet as equal brothers and sisters because of deep feelings or the same purpose, and are called "Yi Di", "Yi Di", "Yi Mei" and "Yi Jie". Now most people in northern China are called "godbrothers", "godbrothers", "godsisters" and "godsisters".
Extended data:
No matter men, women and children, the number of people wishing is not limited, but it must be odd in ancient times. In the same year, the same sex became sworn, with men called brothers and women called sisters. It is usually carried out in adolescence, and most of them are like-minded, or in the same boat, or have their own needs.
In the old society, there were many rituals and customs of becoming sworn: First, people did not become sworn; Second, the in-laws do not become sworn; Third, those who have a generation gap do not become sworn; Fourth, those who do not agree with the eight characters do not become sworn; Fifth, those who break the clan rules do not become sworn (if they had enemies with other clans before, they vowed to make rules not to marry or marry a certain clan, etc.). ).) and so on.
After the ancient swearing-in ceremony, the people who took part in the swearing-in ceremony were called brothers and sisters. Some add the words "Qi", "Lan" and "Friendship" before the address, and some are commonly known as the eldest, the second and the third ... This means sharing weal and woe. In case of wedding, funeral and celebration, etc. They all interact with each other like brothers and sisters.
Baidu encyclopedia-sworn