There is a saying in the Analects of Confucius: sit straight and don't sit. This is the rule. The mat must be straightened. There is also a provision in the Book of Rites: there are five people living in groups, and the seats of the elders are different. If there are more than five people, the respected person must sit on another mat. This gave birth to a great word: chairman.
The original meaning of the chairman is: the person on the main mat, or the main person on the mat. Unlike English chairs, English chairs refer to people sitting in chairs.
President:
Han Shu's "Volume 19" shows that the Taishi, the Taifu and the Taibao are three officials, and they are the towering sons, sitting and discussing politics, all of whom are presidents. The History of the Three Kingdoms Volume 35 Shu Shu Shu Zhugeliang Chuan: So Liang was the right general and became the prime minister, and the president remained the same.
The former leader of the unified army is the president.
The original words of the president are not the president, but the president, which means unified management of the chief executive, but changed to the president because of its roundabout way.