Tianxiang (天象) signifies the various phenomena appearing in the sky, with xiang (象) denoting a visible event of an incorporeal objective presence. The ancient Chinese believed that both celestial bodies, such as the sun, moon, and stars, and meteorological symbols, such as wind, rain, thunder, and lightning, are not corporeal. Therefore, the phenomena manifested by their movement or occurrence are called tianxiang, the heavenly phenomena. Through observation and interpretation of the heavenly phenomena, the ancients attempted to explain the course and norms underlying the operation of nature and, by extension, society.

Xi and He were thus commanded, in reverence for and compliance with the Heaven, to observe and forecast the phenomena formed by the movements of the sun, moon, and stars and to prudently instruct the people in the changing of the seasons. (The Book of History)

In the heaven are phenomena, and on the earth are forms. Their movement demonstrates changes of things. (The Book of Changes)