Di (Chinese: 地; pinyin: dì; Wade–Giles: ti; lit. 'earth') is one of the oldest Chinese terms for the earth and a key concept or figure in Chinese philosophy and religion. It is widely considered to be one of three powers (sāncái, 三才) which are Heaven, Earth, and Humanity (tiān-dì-rén, 天地人).
There is a significant belief in Taoism which focuses on tian, as well as the forces of di (earth) and water, which are held to be equally powerful, instead of earth and humanity.
Tian (天) is one of the oldest Chinese terms for heaven and is a central concept in Chinese mythology, philosophy, and cosmology. During the Shang dynasty (17th–11th century BCE), the highest deity was referred to as Shangdi or Di (帝, "Lord"). In the subsequent Zhou dynasty, Tian became synonymous with this figure. Prior to the 20th century, the worship of Tian was considered an orthodox cosmic principle in China.
In Taoism and Confucianism, Tian (the celestial aspect of the cosmos, often translated as "Heaven") is described in relation to its complementary aspect, Dì (地, often translated as "Earth"). Together, they were understood to represent the two poles of the Three Realms of reality, with Humanity (人, rén) occupying the middle realm, and the lower world inhabited by demons (魔, mó) and spirits or "ghosts" (鬼, guǐ).