上帝 originally referred to a supreme deity in ancient Chinese religion before being adopted by Christian missionaries to translate 'God.' The phrase 顾客就是上帝 ('the customer is God') is a very common business saying in China.
usage
In Chinese, different religions use different terms: 上帝 (Christianity), 真主 (Zhēnzhǔ, Allah in Islam), 佛 (Fó, Buddha). 天 (tiān, heaven) is also used as a general concept of a higher power.