Tiantai is a Chinese word that refers to a philosophical and religious movement that was founded in the 6th century. This movement is also known as the "Lotus School" and is based on the Lotus Sutra, a primary text of Mahayana Buddhism. There are several other terms that can be used as synonyms for tiantai, including the "Tendai School" in Japan, the "Cheontae School" in Korea, and the "Tiantai Zong" or "Tiantai Sect" in China. All of these terms refer to the same philosophical and religious movement that emphasizes the unity of all things and the potential of all beings to achieve enlightenment.