There are three meanings to the term. 1) The five fundamental things or elements that make up all things. The Book of History was the first to define the five elements: metal, wood, water, fire, and earth. Each of these has its own properties and they interact in a generative or destructive relationship. 2) On a more abstract level, the term refers to the basic framework to understand the world. All things can be included in the realm of wuxing (五行) and their properties are explained or understood accordingly. 3) It refers to five kinds of moral behavior. Xunzi once criticized Zisi and Mencius for “creating wuxing on the basis of old theories.” Ancient bamboo slips unearthed from a grave at Guodian dating back to the State of Chu as well as inscribed silk texts from the Mawangdui Tomb of the Western Han Dynasty, all describe this wuxing as benevolence, righteousness, etiquette, wisdom, and character of a sage.
In heaven there are the sun, moon, and stars, while on earth there are the five elements: metal, wood, water, fire, and earth. (Zuo’s Commentary on The Spring and Autumn Annals)
The qi of heaven and that of earth merge into one; it evolves into yin and yang, the four seasons, and the five elements of metal, wood, water, fire, and earth. (Dong Zhongshu: Luxuriant Gems of The Spring and Autumn Annals)
The term has two meanings. First, it refers to the state of one whole mass that existed before the universe took shape, often said to exist before qi (vital force) emerged. The multitude of organisms on earth all emanated from this state. Second, it refers to Chaos, king of the Central Region in a fable in Zhuangzi. According to the fable, Chaos had no eyes, nose, mouth or ears. Shu, king of the South Sea, and Hu, king of the North Sea, drilled seven apertures into Chaos and killed him. Zhuangzi used this story to show the state of chaos of the world in which there is neither knowledge or wisdom, nor distinction between good and evil.
Those who commented on The Book of Changes said, “Before qi (vital force) appeared, the world was in a state of formless chaos.” (Wang Chong: A Comparative Study of Different Schools of Learning)
The king of the South Sea was called Shu, the king of the North Sea was called Hu, and the king of the Central Region was called Chaos. Shu and Hu often met in the territory of Chaos, who treated them very well. They wanted to repay his kindness, and said, “Every man has seven apertures with which to hear, to see, to eat and drink, and to breathe, but Chaos alone has none of them. Let’s try and bore some for him.” They bored one aperture on Chaos each day, and on the seventh day Chaos died. (Zhuangzi)
Selected from Key Concepts in Chinese Thought and Culture published by Foreign Language Teaching and Research Press.