Dan is an ancient hieroglyph. The sky above represents the sun, and the words below represent the earth. This means that the sun rises from the horizon. Therefore, it is morning and sunrise.
To sum up, "New Year's Day" is the morning of the first day of China ancient calendar 1. This is the earliest meaning of New Year's Day. New Year's Day is also called Chen Yuan, Yuan Day and Spring Festival. In other words, the ancient New Year's Day is the Spring Festival, which is the first day of the New Year. Wang Anshi, a famous poet in the Northern Song Dynasty, also wrote a poem "January Day": "The firecrackers are one year old, and the spring breeze warms Tu Su. Thousands of households always exchange new peaches for old ones. " January 1 here refers to the Spring Festival, that is, New Year's Day.