The Dao, also spelled Tao, is a fundamental concept in Chinese philosophy and religion. The word "dao" means "way" or "path" and can function as a noun or a verb, indicating the road upon which one travels, the act of wayfaring or traveling down a road, or even the act of way-making by leading someone down or constructing a road. The Dao is multifaceted and has several interpretations. The most profound interpretation is that of the Cosmic Dao, the Way of the cosmos, which is evident in nature. The Daoists believed that the only human actions which ultimately make sense are those which are in accord with the flow of Nature - the Dao or the Way.

Daoism (Taoism) is a philosophical, ethical or religious tradition that emphasizes living in harmony with the Dao. The term Daoism encompasses thought and practice that sometimes are viewed as philosophical, as religious, or as a combination of both. The Daodejing, a philosophical and spiritual text, teaches that humans cannot fathom the Dao because any name we give to it cannot capture it. Those who experience oneness with the Dao, known as "obtaining dao," will be enabled to wu-wei, which is generally agreed to mean "nonaction" or "no action".

In summary, the Dao is a fundamental concept in Chinese philosophy and religion that refers to the natural way or path of the universe and can be interpreted in various ways. It emphasizes living in harmony with nature and the flow of the universe.