Tian (天) is a sacred and fundamental concept in ancient Chinese philosophy. It has three different meanings. The first is the physical sky or the entirety of nature (not including human society), the operations of which manifest certain laws and order. The second refers to a spiritual being, which possesses an anthropomorphic will and governs everything in the universe. The third denotes the universal law, which is observed by all things and beings, and which is also the basis of human nature, morality, and social and political orders.                      

Citations:

Heaven acts according to its inherent laws. It does not exist due to the virtue of Yao, nor will it disappear because of the tyranny of Jie. (Xunzi)

Heaven trusts and blesses the people.(The Book of History)