What does the zodiac mean?

The great circle in which the earth's orbit around the sun intersects the celestial sphere. Because the earth's revolution is attracted by other planets, the moon and other celestial bodies, the position of the ecliptic plane in space changes irregularly. But in the process of change, the instantaneous orbital plane always passes through the center of the sun. This change can be expressed by a slow long-term movement plus some short-term changes. In view of the complexity of motion changes, it is necessary to use the strict definition of the ecliptic in some astronomical work: at any moment, the orbital plane that only considers long-term motion is called the instantaneous average orbital plane, and the great circle that this plane intersects with the celestial sphere is called the ecliptic. Seen from the center of the earth, the ecliptic is very close to the apparent annual trajectory of the sun in the star. Only by using precise astronomical instruments can we detect the difference between the ecliptic and the apparent annual path of the sun. The ecliptic is the base circle of the ecliptic coordinate system on the celestial sphere.