Tao or Dao refers to a Chinese character that was of pivotal meaning in ancient Chinese philosophy and religion. Tao is central to Taoism, but Confucianism also refers to it. Most debates between proponents of one of the Hundred Schools of Thought could be summarized in the simple question: who is closer to the Tao, or, in other words, whose "Tao" is the most powerful? As used in modern spoken and written Chinese, Tao has a wide scope of usage and meaning. Tao may be rendered as religion, morality, duty, knowledge, rationality, ultimate truth, path, or taste. Its semantics vary widely depending on the context. Tao is generally translated into English as "The Way".

The philosophic and religious use of the character can be analyzed in two main segments: one meaning is "doctrine" or "discourse"; every school owns and defends a specific Tao or discourse about doctrine. In the other meaning, there is the 'Great Tao', that is the source of and guiding principle behind all the processes of the universe. Beyond being and non-being, prior to space and time, Tao is the intelligent ordering principle behind the unceasing flow of change in the natural world. In this sense Tao gains great cosmological and metaphysical significance comparable to the Judaeo-Christian concept of God (albeit stripped of anthropomorphic characteristics); the Greek concept of the logos; or the Dharma in Indian religions.

The nature and meaning of the Tao received its first full exposition in the Daode Jing (Tao Te Ching) of Laozi, a work which along with those of Confucius and Mencius would have a far-reaching effect on the intellectual, moral and religious life of the Chinese people. Although a book of practical wisdom in many ways, its profoundly metaphysical character was unique among the prevailing forms of thought in China at that time. The religion and philosophy based on the teaching of Laozi and his successor Zhuangzi is known in English as "Taoism." Even if often said to be undefinable and unexplainable with words (even Chinese ones), the present article focuses on the Tao of Taoism.