What is the relationship between the four Chinese characters spring, summer, autumn and winter and the four seasons of the year?

Distinguishing seasons by spring, summer, autumn and winter (these four words) is actually related to the revolution of the earth. Our earth revolves around the sun, but also around its own axis, but the axis of the earth is not perpendicular to the orbital plane, but tilted by 23 degrees and 27 minutes. Because of this tilt, the direct point of the sun on the earth's surface moves between the south tropical zone and the north tropical zone, thus forming four seasons: spring, summer, autumn and winter.

In ancient China, four seasons began in beginning of spring, Changchun, beginning of autumn and beginning of winter. On the calendar published in China, next to the date of A.D., there is also a lunar calendar, also called the summer calendar, which is usually called the "lunar calendar". China people are used to dividing the lunar calendar into four seasons: 1 to March, April to June in summer, July to September in autumn, and 10 to 12 in winter.

In the former agricultural society, the progress of farming was always based on the weather, and the calendar naturally became the basis for farmers to work and rest. China has been a big agricultural country since ancient times, and the accuracy of the calendar directly affects the national economy and people's livelihood. Therefore, emperors of all dynasties attached great importance to the revision of calendars. Before the Warring States Period, the calendars used by Huangdi, Zhuan Xu, Xia, Yin, Zhou and Lu dynasties were all four-season calendars. Among them, the calendars of Huangdi, Zhou and Lu are based on the moon, that is, the mid-winter month (November of the lunar calendar) is the first year.

Emperor Wu of the Han Dynasty ordered Sima Qian, Luo and others to change the "Zhuan Xu calendar" of the Qin Dynasty and establish the "taichu calendar", still taking the month in the summer calendar as the beginning of the year and incorporating the 24 solar terms into the calendar. Its name is related to the four solar terms: vernal equinox, summer solstice, autumn equinox and winter solstice.