The word Mid-Autumn Festival was first seen in Zhou Li. Because of the ancient Chinese calendar, August 15 of the lunar calendar happens to be the autumn of a year.

And it is in the middle of August, so it is called "Mid-Autumn Festival".

Introduction to Mid-Autumn Festival:

The Mid-Autumn Festival, also known as Moon Worship Festival, Moonlight Birthday, Moon Night, etc., is celebrated on the 15th day of August of the lunar calendar every year. Since ancient times, Mid-Autumn Festival has had folk customs such as offering sacrifices to the moon, enjoying the moon, eating moon cakes, playing with lanterns, enjoying osmanthus flowers and drinking osmanthus wine, which have spread and lasted for a long time. The Mid-Autumn Festival is a colorful and precious cultural heritage, with the full moon as a sign of people's reunion, as the sustenance of missing their hometown and their loved ones, and hoping for a bumper harvest and happiness.

The Mid-Autumn Festival originated in ancient times, popularized in the Han Dynasty, shaped in the early years of the Tang Dynasty and prevailed after the Song Dynasty. Mid-Autumn Festival is a traditional cultural festival popular in China and Chinese areas around the world. Mid-Autumn Festival, Spring Festival, Tomb-Sweeping Day and Dragon Boat Festival are also called the four traditional festivals in China. Mid-Autumn Festival has been listed as a national legal holiday since 2008. On May 20th, 2006, the People's Republic of China and the State Council of China listed it in the first national intangible cultural heritage list.